Update README.md

test coverage
improved error handling for read() with concurrent close() (#569 )
2024-06-02 15:09:07 +02:00 · 2024-06-02 14:52:39 +02:00 · 2024-06-02 10:16:56 +02:00 · 2024-06-01 14:46:38 +02:00 · 2024-06-01 14:46:38 +02:00 · 2024-06-01 14:46:38 +02:00
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@ -8,11 +8,10 @@ jobs:
    runs-on: ubuntu-latest

    steps:
-    - uses: actions/checkout@v2
-    - name: set up JDK 1.11
-      uses: actions/setup-java@v2
+    - uses: actions/checkout@v3
+    - uses: actions/setup-java@v3
      with:
-        distribution: 'adopt'
-        java-version: '11'
+        distribution: 'temurin'
+        java-version: '17'
    - name: Build with Gradle
      run: ./gradlew assembleDebug
--- a/.idea/.gitignore
+++ b/.idea/.gitignore
@ -2,3 +2,7 @@ caches
 codeStyles
 libraries
 workspace.xml
+androidTestResultsUserPreferences.xml
+appInsightsSettings.xml
+deploymentTargetDropDown.xml
+deploymentTargetSelector.xml
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
  <component name="CompilerConfiguration">
-    <bytecodeTargetLevel target="11" />
+    <bytecodeTargetLevel target="17" />
  </component>
 </project>
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@ -1,4 +1,3 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
  <component name="ExternalStorageConfigurationManager" enabled="true" />
  <component name="NullableNotNullManager">
@ -6,7 +5,7 @@
    <option name="myDefaultNotNull" value="androidx.annotation.NonNull" />
    <option name="myNullables">
      <value>
-        <list size="15">
+        <list size="17">
          <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.Nullable" />
          <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nullable" />
          <item index="2" class="java.lang.String" itemvalue="javax.annotation.CheckForNull" />
@ -22,12 +21,14 @@
          <item index="12" class="java.lang.String" itemvalue="org.eclipse.jdt.annotation.Nullable" />
          <item index="13" class="java.lang.String" itemvalue="io.reactivex.annotations.Nullable" />
          <item index="14" class="java.lang.String" itemvalue="io.reactivex.rxjava3.annotations.Nullable" />
+          <item index="15" class="java.lang.String" itemvalue="org.jspecify.nullness.Nullable" />
+          <item index="16" class="java.lang.String" itemvalue="jakarta.annotation.Nullable" />
        </list>
      </value>
    </option>
    <option name="myNotNulls">
      <value>
-        <list size="14">
+        <list size="16">
          <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.NotNull" />
          <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nonnull" />
          <item index="2" class="java.lang.String" itemvalue="edu.umd.cs.findbugs.annotations.NonNull" />
@ -42,11 +43,13 @@
          <item index="11" class="java.lang.String" itemvalue="org.eclipse.jdt.annotation.NonNull" />
          <item index="12" class="java.lang.String" itemvalue="io.reactivex.annotations.NonNull" />
          <item index="13" class="java.lang.String" itemvalue="io.reactivex.rxjava3.annotations.NonNull" />
+          <item index="14" class="java.lang.String" itemvalue="jakarta.annotation.Nonnull" />
+          <item index="15" class="java.lang.String" itemvalue="org.jspecify.nullness.NonNull" />
        </list>
      </value>
    </option>
  </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="jbr-17" project-jdk-type="JavaSDK">
    <output url="file://$PROJECT_DIR$/build/classes" />
  </component>
  <component name="ProjectType">
--- a/README.md
+++ b/README.md
@ -1,6 +1,6 @@
 [![Actions Status](https://github.com/mik3y/usb-serial-for-android/workflows/build/badge.svg)](https://github.com/mik3y/usb-serial-for-android/actions)
 [![Jitpack](https://jitpack.io/v/mik3y/usb-serial-for-android.svg)](https://jitpack.io/#mik3y/usb-serial-for-android)
-[![Codacy](https://app.codacy.com/project/badge/Grade/ef799bba8a7343818af0a90eba3ecb46)](https://www.codacy.com/gh/kai-morich/usb-serial-for-android-mik3y/dashboard?utm_source=github.com&amp;utm_medium=referral&amp;utm_content=kai-morich/usb-serial-for-android-mik3y&amp;utm_campaign=Badge_Grade)
+[![Codacy](https://app.codacy.com/project/badge/Grade/ef799bba8a7343818af0a90eba3ecb46)](https://app.codacy.com/gh/kai-morich/usb-serial-for-android-mik3y/dashboard?utm_source=gh&utm_medium=referral&utm_content=&utm_campaign=Badge_grade)
 [![codecov](https://codecov.io/gh/mik3y/usb-serial-for-android/branch/master/graph/badge.svg)](https://codecov.io/gh/mik3y/usb-serial-for-android)

 # usb-serial-for-android
@ -26,10 +26,26 @@ allprojects {
    }
 }
 ```
+
+Starting with gradle 6.8 you can alternatively add jitpack.io repository to your settings.gradle:
+```gradle
+dependencyResolutionManagement {
+    repositories {
+        ...
+        maven { url 'https://jitpack.io' }
+    }
+}
+```
+
+If using gradle kotlin  use line
+```gradle.kts
+        maven(url = "https://jitpack.io")
+```
+
 Add library to dependencies
 ```gradle
 dependencies {
-    implementation 'com.github.mik3y:usb-serial-for-android:3.4.3'
+    implementation 'com.github.mik3y:usb-serial-for-android:3.7.3'
 }
 ```

@ -113,22 +129,23 @@ new device or for one using a custom VID/PID pair.
 UsbSerialProber is a class to help you find and instantiate compatible
 UsbSerialDrivers from the tree of connected UsbDevices.  Normally, you will use
 the default prober returned by ``UsbSerialProber.getDefaultProber()``, which
-uses the built-in list of well-known VIDs and PIDs that are supported by our
-drivers.
+uses USB interface types and the built-in list of well-known VIDs and PIDs that
+are supported by our drivers.

 To use your own set of rules, create and use a custom prober:

 ```java
-// Probe for our custom CDC devices, which use VID 0x1234
-// and PIDS 0x0001 and 0x0002.
+// Probe for our custom FTDI device, which use VID 0x1234 and PID 0x0001 and 0x0002.
 ProbeTable customTable = new ProbeTable();
-customTable.addProduct(0x1234, 0x0001, CdcAcmSerialDriver.class);
-customTable.addProduct(0x1234, 0x0002, CdcAcmSerialDriver.class);
+customTable.addProduct(0x1234, 0x0001, FtdiSerialDriver.class);
+customTable.addProduct(0x1234, 0x0002, FtdiSerialDriver.class);

 UsbSerialProber prober = new UsbSerialProber(customTable);
 List<UsbSerialDriver> drivers = prober.findAllDrivers(usbManager);
 // ...
 ```
+*Note*: as of v3.5.0 this library detects CDC devices by USB interface types instead of fixed VID+PID,
+so custom probers are typically not required any more for CDC devices.

 Of course, nothing requires you to use UsbSerialProber at all: you can
 instantiate driver classes directly if you know what you're doing; just supply
@ -139,15 +156,19 @@ a compatible UsbDevice.
 This library supports USB to serial converter chips:
 * FTDI FT232R, FT232H, FT2232H, FT4232H, FT230X, FT231X, FT234XD
 * Prolific PL2303
-* Silabs CP2102 and all other CP210x
-* Qinheng CH340, CH341A
+* Silabs CP2102, CP210*
+* Qinheng CH340, CH341A, CH9102

-and devices implementing the CDC/ACM protocol like
+devices implementing the CDC/ACM protocol like
 * Arduino using ATmega32U4
 * Digispark using V-USB software USB
 * BBC micro:bit using ARM mbed DAPLink firmware
 * ...

+and some device specific drivers:
+* GsmModem devices, e.g. for Unisoc based Fibocom GSM modems
+* Chrome OS CCD (Closed Case Debugging)
+
 ## Help & Discussion

 For common problems, see the [FAQ](https://github.com/mik3y/usb-serial-for-android/wiki/FAQ) wiki page.
--- a/build.gradle
+++ b/build.gradle
@ -6,7 +6,7 @@ buildscript {
        google()
    }
    dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.2'
+        classpath 'com.android.tools.build:gradle:8.4.0'
    }
 }

--- a/codecov.yml
+++ b/codecov.yml
@ -0,0 +1,5 @@
+codecov:
+  max_report_age: off
+  require_ci_to_pass: no
+  notify:
+    wait_for_ci: no
--- a/gradle.properties
+++ b/gradle.properties
@ -1,2 +1,3 @@
-#android.enableJetifier=true
+android.enableJetifier=true
 android.useAndroidX=true
+android.defaults.buildfeatures.buildconfig=true
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-all.zip
--- a/jitpack.yml
+++ b/jitpack.yml
@ -1,4 +1,4 @@
 jdk:
-  - openjdk11
+  - openjdk17
 install:
  - ./gradlew :usbSerialForAndroid:publishToMavenLocal
--- a/test/pi_pico/README.md
+++ b/test/pi_pico/README.md
@ -0,0 +1,6 @@
+
+# `tinyusb_dev_cdc_dual_ports.uf2`
+
+compiled from `C:/Program Files/Raspberry Pi/Pico SDK v1.5.1/pico-sdk/lib/tinyusb/examples/device/cdc_dual_ports`
+to `C:/Users/` _user_`/Documents/Pico-v1.5.1/pico-examples/build/usb/device/tinyusb_device_examples/cdc_dual_ports/tinyusb_dev_cdc_dual_ports.uf2`
+
--- a/test/pi_pico/tinyusb_dev_cdc_dual_ports.uf2
+++ b/test/pi_pico/tinyusb_dev_cdc_dual_ports.uf2
--- a/usbSerialExamples/build.gradle
+++ b/usbSerialExamples/build.gradle
@ -3,8 +3,7 @@ plugins {
 }

 android {
-    compileSdkVersion 30
-    buildToolsVersion '30.0.3'
+    compileSdkVersion 34

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
@ -13,10 +12,9 @@ android {

    defaultConfig {
        minSdkVersion 17
-        targetSdkVersion 30
+        targetSdkVersion 34
        vectorDrawables.useSupportLibrary = true

-        testInstrumentationRunner "android.test.InstrumentationTestRunner"
        missingDimensionStrategy 'device', 'anyDevice'
    }

@ -25,10 +23,11 @@ android {
            minifyEnabled true
        }
    }
+    namespace 'com.hoho.android.usbserial.examples'
 }

 dependencies {
    implementation project(':usbSerialForAndroid')
-    implementation 'androidx.appcompat:appcompat:1.3.1'
-    implementation 'com.google.android.material:material:1.4.0'
+    implementation 'androidx.appcompat:appcompat:1.6.1'
+    implementation 'com.google.android.material:material:1.11.0'
 }
--- a/usbSerialExamples/src/main/AndroidManifest.xml
+++ b/usbSerialExamples/src/main/AndroidManifest.xml
@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
-    package="com.hoho.android.usbserial.examples">
+    xmlns:tools="http://schemas.android.com/tools">

    <!-- mipmap/ic_launcher created with Android Studio -> New -> Image Asset using @color/colorPrimary and USB clip art -->
    <application
@ -15,9 +14,9 @@
             when the settings activity is currently shown -->
        <activity
            android:name=".MainActivity"
-            android:label="@string/app_name"
            android:launchMode="singleTask"
-            android:windowSoftInputMode="stateHidden|adjustResize">
+            android:windowSoftInputMode="stateHidden|adjustResize"
+            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
--- a/usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/CustomProber.java
+++ b/usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/CustomProber.java
@ -1,6 +1,6 @@
 package com.hoho.android.usbserial.examples;

-import com.hoho.android.usbserial.driver.CdcAcmSerialDriver;
+import com.hoho.android.usbserial.driver.FtdiSerialDriver;
 import com.hoho.android.usbserial.driver.ProbeTable;
 import com.hoho.android.usbserial.driver.UsbSerialProber;

@ -14,7 +14,8 @@ class CustomProber {

    static UsbSerialProber getCustomProber() {
        ProbeTable customTable = new ProbeTable();
-        customTable.addProduct(0x16d0, 0x087e, CdcAcmSerialDriver.class); // e.g. Digispark CDC
+        customTable.addProduct(0x1234, 0x0001, FtdiSerialDriver.class); // e.g. device with custom VID+PID
+        customTable.addProduct(0x1234, 0x0002, FtdiSerialDriver.class); // e.g. device with custom VID+PID
        return new UsbSerialProber(customTable);
    }

--- a/usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/TerminalFragment.java
+++ b/usbSerialExamples/src/main/java/com/hoho/android/usbserial/examples/TerminalFragment.java
@ -8,6 +8,7 @@ import android.content.IntentFilter;
 import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbManager;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
@ -27,6 +28,7 @@ import android.widget.ToggleButton;

 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.Fragment;

 import com.hoho.android.usbserial.driver.UsbSerialDriver;
@ -88,12 +90,22 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag
        withIoManager = getArguments().getBoolean("withIoManager");
    }

+    @Override
+    public void onStart() {
+        super.onStart();
+        ContextCompat.registerReceiver(getActivity(), broadcastReceiver, new IntentFilter(INTENT_ACTION_GRANT_USB), ContextCompat.RECEIVER_NOT_EXPORTED);
+    }
+
+    @Override
+    public void onStop() {
+        getActivity().unregisterReceiver(broadcastReceiver);
+        super.onStop();
+    }
+
    @Override
    public void onResume() {
        super.onResume();
-        getActivity().registerReceiver(broadcastReceiver, new IntentFilter(INTENT_ACTION_GRANT_USB));
-
-        if(usbPermission == UsbPermission.Unknown || usbPermission == UsbPermission.Granted)
+        if(!connected && (usbPermission == UsbPermission.Unknown || usbPermission == UsbPermission.Granted))
            mainLooper.post(this::connect);
    }

@ -103,7 +115,6 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag
            status("disconnected");
            disconnect();
        }
-        getActivity().unregisterReceiver(broadcastReceiver);
        super.onPause();
    }

@ -211,7 +222,10 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag
        UsbDeviceConnection usbConnection = usbManager.openDevice(driver.getDevice());
        if(usbConnection == null && usbPermission == UsbPermission.Unknown && !usbManager.hasPermission(driver.getDevice())) {
            usbPermission = UsbPermission.Requested;
-            PendingIntent usbPermissionIntent = PendingIntent.getBroadcast(getActivity(), 0, new Intent(INTENT_ACTION_GRANT_USB), 0);
+            int flags = Build.VERSION.SDK_INT >= Build.VERSION_CODES.M ? PendingIntent.FLAG_MUTABLE : 0;
+            Intent intent = new Intent(INTENT_ACTION_GRANT_USB);
+            intent.setPackage(getActivity().getPackageName());
+            PendingIntent usbPermissionIntent = PendingIntent.getBroadcast(getActivity(), 0, intent, flags);
            usbManager.requestPermission(driver.getDevice(), usbPermissionIntent);
            return;
        }
@ -225,7 +239,11 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag

        try {
            usbSerialPort.open(usbConnection);
-            usbSerialPort.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
+            try{
+                usbSerialPort.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
+            }catch (UnsupportedOperationException e){
+                status("unsupport setparameters");
+            }
            if(withIoManager) {
                usbIoManager = new SerialInputOutputManager(usbSerialPort, this);
                usbIoManager.start();
@ -349,7 +367,7 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag
                cdBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.CD));
                riBtn.setChecked(controlLines.contains(UsbSerialPort.ControlLine.RI));
                mainLooper.postDelayed(runnable, refreshInterval);
-            } catch (IOException e) {
+            } catch (Exception e) {
                status("getControlLines() failed: " + e.getMessage() + " -> stopped control line refresh");
            }
        }
@ -366,8 +384,15 @@ public class TerminalFragment extends Fragment implements SerialInputOutputManag
                if (!controlLines.contains(UsbSerialPort.ControlLine.CD))   cdBtn.setVisibility(View.INVISIBLE);
                if (!controlLines.contains(UsbSerialPort.ControlLine.RI))   riBtn.setVisibility(View.INVISIBLE);
                run();
-            } catch (IOException e) {
+            } catch (Exception e) {
                Toast.makeText(getActivity(), "getSupportedControlLines() failed: " + e.getMessage(), Toast.LENGTH_SHORT).show();
+                rtsBtn.setVisibility(View.INVISIBLE);
+                ctsBtn.setVisibility(View.INVISIBLE);
+                dtrBtn.setVisibility(View.INVISIBLE);
+                dsrBtn.setVisibility(View.INVISIBLE);
+                cdBtn.setVisibility(View.INVISIBLE);
+                cdBtn.setVisibility(View.INVISIBLE);
+                riBtn.setVisibility(View.INVISIBLE);
            }
        }

--- a/usbSerialExamples/src/main/res/xml/device_filter.xml
+++ b/usbSerialExamples/src/main/res/xml/device_filter.xml
@ -32,4 +32,7 @@
    <usb-device vendor-id="7855" product-id="4"    /> <!-- 0x1eaf / 0x0004: Leaflabs Maple -->
    <usb-device vendor-id="3368" product-id="516"  /> <!-- 0x0d28 / 0x0204: ARM mbed -->
    <usb-device vendor-id="1155" product-id="22336" /><!-- 0x0483 / 0x5740: ST CDC -->
+    <usb-device vendor-id="11914" product-id="5"   /> <!-- 0x2E8A / 0x0005: Raspberry Pi Pico Micropython -->
+    <usb-device vendor-id="11914" product-id="10"  /> <!-- 0x2E8A / 0x000A: Raspberry Pi Pico SDK -->
+    <usb-device vendor-id="6790" product-id="21972" /><!-- 0x1A86 / 0x55D4: Qinheng CH9102F -->
 </resources>
--- a/usbSerialForAndroid/build.gradle
+++ b/usbSerialForAndroid/build.gradle
@ -4,17 +4,16 @@ plugins {
 }

 android {
-    compileSdkVersion 30
-    buildToolsVersion '30.0.3'
+    compileSdkVersion 34

    defaultConfig {
        minSdkVersion 17
-        targetSdkVersion 30
+        targetSdkVersion 34
        consumerProguardFiles 'proguard-rules.pro'
        
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        testInstrumentationRunnerArguments = [                    // Raspi   Windows   LinuxVM   ...
-                'rfc2217_server_host': '192.168.0.100',
+                'rfc2217_server_host': '192.168.0.78',
                'rfc2217_server_nonstandard_baudrates': 'true',   // true    false     false
        ]
    }
@ -22,15 +21,23 @@ android {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
+    namespace 'com.hoho.android.usbserial'
+    publishing {
+        // if coverage is enabled, change 'release' to 'anyDeviceRelease' or comment out publishing rule
+        singleVariant('release') {
+            withSourcesJar()
+        }
+    }
 }

 dependencies {
-    implementation "androidx.annotation:annotation:1.2.0"
+    implementation "androidx.annotation:annotation:1.8.0"
    testImplementation 'junit:junit:4.13.2'
-    testImplementation 'org.mockito:mockito-core:1.10.19'
-    androidTestImplementation 'com.android.support.test:runner:1.0.2'
-    androidTestImplementation 'commons-net:commons-net:3.8.0'
-    androidTestImplementation 'org.apache.commons:commons-lang3:3.11'
+    testImplementation 'org.mockito:mockito-core:5.12.0'
+    androidTestImplementation 'androidx.test:core:1.5.0'
+    androidTestImplementation 'androidx.test:runner:1.5.2'
+    androidTestImplementation 'commons-net:commons-net:3.10.0'
+    androidTestImplementation 'org.apache.commons:commons-lang3:3.14.0'
 }

 // gradle task: publishToMavenLocal
@ -39,20 +46,14 @@ project.afterEvaluate {
        publications {
            release(MavenPublication) {
                from components.release
-                artifact androidSourcesJar

                // values used for local maven repo, jitpack uses github release:
                groupId 'com.github.mik3y'
                artifactId 'usb-serial-for-android'
-                version 'v3.5.0beta'
+                version '3.7.3beta'
            }
        }
    }
 }

-task androidSourcesJar(type: Jar) {
-    classifier 'sources'
-    from android.sourceSets.main.java.srcDirs
-}
-
 //apply from: 'coverage.gradle'
--- a/usbSerialForAndroid/coverage.gradle
+++ b/usbSerialForAndroid/coverage.gradle
@ -2,7 +2,7 @@
 apply plugin: 'jacoco'

 android {
-    flavorDimensions 'device'
+    flavorDimensions += 'device'
    productFlavors {
        anyDevice {
            // Used as fallback in usbSerialExample/build.gradle -> missingDimensionStrategy, but not for coverage report
@ -48,7 +48,8 @@ android {

    buildTypes {
        debug {
-            testCoverageEnabled true // disable for testAnyDeviceDebugUnitTest
+            enableUnitTestCoverage true
+            enableAndroidTestCoverage true
        }
    }
 }
@ -60,20 +61,18 @@ project.gradle.taskGraph.whenReady {
    }
 }

-task jacocoTestReport(type: JacocoReport ,
-        dependsOn: ['compileAnyDeviceDebugSources' /*'testAnyDeviceDebugUnitTest' , 'create<device>DebugCoverageReport'*/]) {
-    reports {
-        xml.enabled = true
-        html.enabled = true
-    }
-
+task jacocoTestReport(type: JacocoReport, dependsOn: ['compileAnyDeviceDebugSources'
+                                                  /*, 'testAnyDeviceDebugUnitTest' */
+                                                  /*, 'create<device>DebugCoverageReport' */]) {
    def fileFilter = ['**/R.class', '**/R$*.class', '**/BuildConfig.*', '**/Manifest*.*', '**/*Test*.*', 'android/**/*.*']
    def debugTree = fileTree(dir: "$project.buildDir/intermediates/javac/anyDeviceDebug", excludes: fileFilter)
    def mainSrc = "$project.projectDir/src/main/java"

+    reports.xml.required = true
    sourceDirectories.from files([mainSrc])
    classDirectories.from files([debugTree])
    executionData.from fileTree(dir: project.buildDir, includes: [
-            'jacoco/testAnyDeviceDebugUnitTest.exec', 'outputs/code_coverage/*AndroidTest/connected/*.ec'
+            'outputs/unit_test_code_coverage/anyDeviceDebugUnitTest/testAnyDeviceDebugUnitTest.exec',
+            'outputs/code_coverage/*DebugAndroidTest/connected/*/coverage.ec'
    ])
 }
--- a/usbSerialForAndroid/src/androidTest/AndroidManifest.xml
+++ b/usbSerialForAndroid/src/androidTest/AndroidManifest.xml
@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-      package="com.hoho.android.usbserial"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-permission android:name="android.permission.INTERNET"/>
--- a/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/CrossoverTest.java
+++ b/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/CrossoverTest.java
@ -7,13 +7,15 @@ package com.hoho.android.usbserial;

 import android.content.Context;
 import android.hardware.usb.UsbManager;
-import android.support.test.InstrumentationRegistry;
-import android.support.test.runner.AndroidJUnit4;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
 import android.util.Log;

 import com.hoho.android.usbserial.driver.UsbSerialDriver;
 import com.hoho.android.usbserial.driver.UsbSerialPort;
 import com.hoho.android.usbserial.driver.UsbSerialProber;
+import com.hoho.android.usbserial.util.TestBuffer;
 import com.hoho.android.usbserial.util.UsbWrapper;

 import org.junit.Before;
@ -24,12 +26,14 @@ import org.junit.rules.TestWatcher;
 import org.junit.runner.Description;
 import org.junit.runner.RunWith;

+import java.io.IOException;
 import java.util.EnumSet;
 import java.util.List;

 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
 import static org.junit.Assume.assumeTrue;
@ -55,7 +59,7 @@ public class CrossoverTest {
        assumeTrue("ignore test for device specific coverage report",
                InstrumentationRegistry.getArguments().getString("test_device_driver") == null);

-        context = InstrumentationRegistry.getContext();
+        context = ApplicationProvider.getApplicationContext();
        usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
        List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(usbManager);
        assertNotEquals("no USB device found", 0, availableDrivers.size());
@ -160,4 +164,53 @@ public class CrossoverTest {
        usb2.close();
    }

+    @Test
+    public void concurrent() throws Exception {
+        // 115200 baud ~= 11kB/sec => ~1.5 second test duration with 16kB tbuf
+        // concurrent (+ blocking) write calls as tbuf larger than any buffer size returned by UsbWrapper.getWriteSizes()
+        // concurrent read calls in IoManager threads
+        TestBuffer tbuf1 = new TestBuffer(16*1024);
+        TestBuffer tbuf2 = new TestBuffer(16*1024);
+
+        class WriteRunnable implements Runnable {
+            public WriteRunnable(int port) { this.port = port; }
+            private final int port;
+            Exception exc;
+            @Override
+            public void run() {
+                byte[] buf = new byte[1024];
+                try {
+                    for(int i=0; i<tbuf1.buf.length / 1024; i++) {
+                        System.arraycopy(tbuf1.buf, i*1024, buf, 0, 1024);
+                        if (port == 1)
+                            usb1.write(buf);
+                        else
+                            usb2.write(buf);
+                    }
+                } catch (IOException exc) {
+                    this.exc = exc;
+                }
+            }
+        }
+
+        usb1.open();
+        usb2.open();
+        usb1.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb2.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
+        WriteRunnable wr1 = new WriteRunnable(1), wr2 = new WriteRunnable(2);
+        Thread wt1 = new Thread(wr1), wt2 = new Thread(wr2);
+        boolean done1 = false, done2 = false;
+        wt1.start();
+        Thread.sleep(50);
+        wt2.start();
+        while(!done1 && !done2) {
+            if(!done1)
+                done1 = tbuf1.testRead(usb1.read(-1));
+            if(!done2)
+                done2 = tbuf2.testRead(usb2.read(-1));
+        }
+        wt1.join(); wt2.join();
+        assertNull(wr1.exc);
+        assertNull(wr2.exc);
+    }
 }
--- a/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/DeviceTest.java
+++ b/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/DeviceTest.java
@ -15,30 +15,35 @@ import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbManager;
 import android.os.Process;
-import android.support.test.InstrumentationRegistry;
-import android.support.test.runner.AndroidJUnit4;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
 import android.util.Log;

 import com.hoho.android.usbserial.driver.CdcAcmSerialDriver;
 import com.hoho.android.usbserial.driver.Ch34xSerialDriver;
+import com.hoho.android.usbserial.driver.ChromeCcdSerialDriver;
 import com.hoho.android.usbserial.driver.CommonUsbSerialPort;
+import com.hoho.android.usbserial.driver.CommonUsbSerialPortWrapper;
 import com.hoho.android.usbserial.driver.Cp21xxSerialDriver;
 import com.hoho.android.usbserial.driver.FtdiSerialDriver;
+import com.hoho.android.usbserial.driver.GsmModemSerialDriver;
 import com.hoho.android.usbserial.driver.ProbeTable;
 import com.hoho.android.usbserial.driver.ProlificSerialDriver;
-import com.hoho.android.usbserial.driver.ProlificWrapper;
+import com.hoho.android.usbserial.driver.ProlificSerialPortWrapper;
 import com.hoho.android.usbserial.driver.SerialTimeoutException;
-import com.hoho.android.usbserial.driver.UsbId;
 import com.hoho.android.usbserial.driver.UsbSerialDriver;
 import com.hoho.android.usbserial.driver.UsbSerialPort;
 import com.hoho.android.usbserial.driver.UsbSerialProber;
 import com.hoho.android.usbserial.util.SerialInputOutputManager;
 import com.hoho.android.usbserial.util.TelnetWrapper;
+import com.hoho.android.usbserial.util.TestBuffer;
 import com.hoho.android.usbserial.util.UsbWrapper;
+import com.hoho.android.usbserial.driver.UsbSerialPort.ControlLine;
+

 import org.junit.After;
 import org.junit.AfterClass;
-import org.junit.Assert;
 import org.junit.Assume;
 import org.junit.Before;
 import org.junit.BeforeClass;
@ -60,13 +65,14 @@ import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;

 import static org.hamcrest.CoreMatchers.anyOf;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;

@ -85,7 +91,6 @@ public class DeviceTest {
    private UsbManager usbManager;
    UsbWrapper usb;
    static TelnetWrapper telnet;
-    private boolean isCp21xxRestrictedPort = false; // second port of Cp2105 has limited dataBits, stopBits, parity

    @Rule
    public TestRule watcher = new TestWatcher() {
@ -110,7 +115,7 @@ public class DeviceTest {
    public void setUp() throws Exception {
        telnet.setUp();

-        context = InstrumentationRegistry.getContext();
+        context = ApplicationProvider.getApplicationContext();
        usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
        List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(usbManager);
        if(availableDrivers.isEmpty()) {
@ -129,7 +134,6 @@ public class DeviceTest {
        usb.setUp();

        Log.i(TAG, "Using USB device "+ usb.serialPort.toString()+" driver="+usb.serialDriver.getClass().getSimpleName());
-        isCp21xxRestrictedPort = usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size()==2 && test_device_port == 1;
        telnet.read(-1); // doesn't look related here, but very often after usb permission dialog the first test failed with telnet garbage
    }

@ -145,34 +149,6 @@ public class DeviceTest {
        telnet.tearDownFixture();
    }

-    private static class TestBuffer {
-        private final byte[] buf;
-        private int len;
-
-        private TestBuffer(int length) {
-            len = 0;
-            buf = new byte[length];
-            int i=0;
-            int j=0;
-            for(j=0; j<length/16; j++)
-                for(int k=0; k<16; k++)
-                    buf[i++]=(byte)j;
-            while(i<length)
-                buf[i++]=(byte)j;
-        }
-
-        private boolean testRead(byte[] data) {
-            assertNotEquals(0, data.length);
-            assertTrue("got " + (len+data.length) +" bytes", (len+data.length) <= buf.length);
-            for(int j=0; j<data.length; j++)
-                assertEquals("at pos "+(len+j), (byte)((len+j)/16), data[j]);
-            len += data.length;
-            //Log.d(TAG, "read " + len);
-            return len == buf.length;
-        }
-    }
-
-
    // clone of org.apache.commons.lang3.StringUtils.indexOfDifference + optional startpos
    private static int indexOfDifference(final CharSequence cs1, final CharSequence cs2) {
        return indexOfDifference(cs1, cs2, 0, 0);
@ -229,7 +205,7 @@ public class DeviceTest {
        doReadWrite(reason, -1);
    }
    private void doReadWrite(String reason, int readWait) throws Exception {
-        byte[] buf1 = new byte[]{ 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x55, 0x55};
+        byte[] buf1 = new byte[]{ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x55, 0x55};
        byte[] buf2 = new byte[]{ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x55, 0x55};
        byte[] data;

@ -259,6 +235,12 @@ public class DeviceTest {

    @Test
    public void openClose() throws Exception {
+        try {
+            usb.serialPort.open(null);
+            fail("null connection error expected");
+        } catch (IllegalArgumentException ignored) {
+        }
+
        usb.open();
        telnet.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
        usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
@ -279,13 +261,15 @@ public class DeviceTest {
        }
        try {
            usb.write(new byte[]{0x00});
-            fail("write error expected");
-        } catch (IOException ignored) {
+            fail("write closed expected");
+        } catch(IOException ex) {
+            assertEquals("Connection closed", ex.getMessage());
        }
        try {
            usb.read(1);
-            fail("read error expected");
-        } catch (IOException ignored) {
+            fail("read closed expected");
+        } catch(IOException ex) {
+            assertEquals("Connection closed", ex.getMessage());
        }
        try {
            usb.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
@ -307,10 +291,59 @@ public class DeviceTest {
                break;
            Thread.sleep(1);
        }
+        try {
+            usb.read();
+            fail("closed expected");
+        } catch (IOException ex) {
+            assertEquals("java.io.IOException: Connection closed", ex.getMessage());
+        }
        // assertEquals(SerialInputOutputManager.State.STOPPED, usb.usbIoManager.getState());
        // unstable. null'ify not-stopped ioManager, else usbClose would try again
        if(SerialInputOutputManager.State.STOPPED != usb.ioManager.getState())
            usb.ioManager = null;
+        usb.close();
+
+        // close while waiting in read
+        class CloseRunnable implements Runnable {
+            boolean wait;
+            public void run() {
+                try {
+                    while(wait)
+                        Thread.sleep(1);
+                    Thread.sleep(5);
+                } catch (InterruptedException ignored) {
+                }
+                Log.d(TAG, "close");
+                usb.close();
+            }
+        }
+        usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
+        CloseRunnable closer = new CloseRunnable();
+        closer.wait = true;
+        Thread th = new Thread(closer);
+        th.start();
+        try {
+            closer.wait = false;
+            usb.serialPort.read(new byte[256], 2000);
+
+            fail("closed expected");
+        } catch(IOException ex) {
+            assertFalse(usb.serialPort.isOpen());
+            assertEquals("Connection closed", ex.getMessage());
+        }
+        th.join();
+        closer.wait = true;
+        th = new Thread(closer);
+        th.start();
+        try {
+            closer.wait = false;
+            usb.serialPort.read(new byte[256], 0);
+            fail("closed expected");
+        } catch(IOException ex) {
+            assertFalse(usb.serialPort.isOpen());
+            assertEquals("Connection closed", ex.getMessage());
+        }
+        th.join();
    }

    @Test
@ -323,9 +356,9 @@ public class DeviceTest {
                403200, 460800, 614400, 806400, 921600, 1228800, 2457600, 3000000, /*6000000*/
        };
        usb.open();
-        Assume.assumeFalse("only for non PL2303G*", ProlificWrapper.isDeviceTypeHxn(usb.serialPort)); // HXN does not use divisor
+        Assume.assumeFalse("only for non PL2303G*", ProlificSerialPortWrapper.isDeviceTypeHxn(usb.serialPort)); // HXN does not use divisor

-        int minBaudRate = ProlificWrapper.isDeviceTypeT(usb.serialPort) ? 6 : 46;
+        int minBaudRate = ProlificSerialPortWrapper.isDeviceTypeT(usb.serialPort) ? 6 : 46;
        try {
            usb.setParameters(minBaudRate-1, 8, 1, UsbSerialPort.PARITY_NONE);
            fail("baud rate to low expected");
@ -505,7 +538,7 @@ public class DeviceTest {
        }

        for(int baudRate : new int[] {300, 2400, 19200, 115200} ) {
-            if(baudRate == 300 && isCp21xxRestrictedPort) {
+            if(baudRate == 300 && usb.isCp21xxRestrictedPort) {
                try {
                    usb.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
                    fail("baudrate 300 on cp21xx restricted port");
@ -518,7 +551,7 @@ public class DeviceTest {

            doReadWrite(baudRate+"/8N1");
        }
-        if(rfc2217_server_nonstandard_baudrates && !isCp21xxRestrictedPort) {
+        if(rfc2217_server_nonstandard_baudrates && !usb.isCp21xxRestrictedPort) {
            usb.setParameters(42000, 8, 1, UsbSerialPort.PARITY_NONE);
            telnet.setParameters(42000, 8, 1, UsbSerialPort.PARITY_NONE);

@ -604,7 +637,7 @@ public class DeviceTest {
            data = telnet.read(2);
            assertThat("19000/7N1", data, equalTo(new byte[]{(byte) 0x80, (byte) 0xff}));
        } catch (UnsupportedOperationException e) {
-                if(!isCp21xxRestrictedPort)
+                if(!usb.isCp21xxRestrictedPort)
                    throw e;
        }
        try {
@ -615,7 +648,7 @@ public class DeviceTest {
            data = telnet.read(2);
            assertThat("19000/6N1", data, equalTo(new byte[]{(byte) 0xc0, (byte) 0xff}));
        } catch (UnsupportedOperationException e) {
-            if (!(isCp21xxRestrictedPort || usb.serialDriver instanceof FtdiSerialDriver))
+            if (!(usb.isCp21xxRestrictedPort || usb.serialDriver instanceof FtdiSerialDriver))
                throw e;
        }
        try {
@ -626,7 +659,7 @@ public class DeviceTest {
            data = telnet.read(2);
            assertThat("19000/5N1", data, equalTo(new byte[] {(byte)0xe0, (byte)0xff}));
        } catch (UnsupportedOperationException e) {
-            if (!(isCp21xxRestrictedPort || usb.serialDriver instanceof FtdiSerialDriver))
+            if (!(usb.isCp21xxRestrictedPort || usb.serialDriver instanceof FtdiSerialDriver))
                throw e;
        }
    }
@ -649,7 +682,7 @@ public class DeviceTest {
            } catch (IllegalArgumentException ignored) {
            }
        }
-        if(isCp21xxRestrictedPort) {
+        if(usb.isCp21xxRestrictedPort) {
            usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
            usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_EVEN);
            usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_ODD);
@ -779,7 +812,7 @@ public class DeviceTest {
                data = telnet.read(2);
                assertThat("19200/8N1", data, equalTo(new byte[]{1, 11}));
            } catch(UnsupportedOperationException e) {
-                if(!isCp21xxRestrictedPort)
+                if(!usb.isCp21xxRestrictedPort)
                    throw e;
            }
            try {
@ -816,33 +849,24 @@ public class DeviceTest {
        assertEquals(availableDrivers.get(0).getClass(), usb.serialDriver.getClass());
    }

-    // return [write packet size, write buffer size(s)]
-    private int[] getWriteSizes() {
-        if (usb.serialDriver instanceof Cp21xxSerialDriver) {
-            if (usb.serialDriver.getPorts().size() == 1) return new int[]{64, 576};
-            else if (usb.serialPort.getPortNumber() == 0) return new int[]{64, 320};
-            else return new int[]{32, 128, 160}; // write buffer size detection is unreliable
-        } else if (usb.serialDriver instanceof Ch34xSerialDriver) {
-            return new int[]{32, 64};
-        } else if (usb.serialDriver instanceof ProlificSerialDriver) {
-            return new int[]{64, 256};
-        } else if (usb.serialDriver instanceof FtdiSerialDriver) {
-            switch (usb.serialDriver.getPorts().size()) {
-                case 1: return new int[]{64, 128};
-                case 2: return new int[]{512, 4096};
-                case 4: return new int[]{512, 2048};
-                default: return null;
-            }
-        } else if (usb.serialDriver instanceof CdcAcmSerialDriver) {
-            return new int[]{64, 128};
-        } else {
-            return null;
-        }
-    }
-
    @Test
-    public void writeTimeout() throws Exception {
+    public void writeSizes() throws Exception {
+        assertNull(CommonUsbSerialPortWrapper.getWriteBuffer(usb.serialPort));
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(12);
+        assertEquals(12, CommonUsbSerialPortWrapper.getWriteBuffer(usb.serialPort).length);
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(-1);
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(-1);
+        assertNull(CommonUsbSerialPortWrapper.getWriteBuffer(usb.serialPort));
        usb.open();
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(12);
+        assertEquals(12, CommonUsbSerialPortWrapper.getWriteBuffer(usb.serialPort).length);
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(-1);
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(-1);
+        assertEquals(usb.serialPort.getWriteEndpoint().getMaxPacketSize(),
+                     CommonUsbSerialPortWrapper.getWriteBuffer(usb.serialPort).length);
+        assertEquals(usb.serialPort.getWriteEndpoint().getMaxPacketSize(),
+                     usb.serialPort.getReadEndpoint().getMaxPacketSize());
+
        int baudRate = 300;
        if(usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() > 1)
            baudRate = 2400;
@ -866,27 +890,32 @@ public class DeviceTest {

        int writeBufferSize = writePacketSize * writePackets;
        Log.d(TAG, "write packet size = " + writePacketSize + ", write buffer size = " + writeBufferSize);
-        int[] writeSizes = getWriteSizes();
-        assertNotNull(writeSizes);
-        assertEquals("write packet size", writeSizes[0], writePacketSize);
-        assertTrue("write buffer size", Arrays.binarySearch(writeSizes, writeBufferSize) > 0);
-        purgeWriteBuffer(purgeTimeout);
-        if(usb.serialDriver instanceof CdcAcmSerialDriver)
-            return; // serial processing to slow for tests below, but they anyway only check shared code in CommonUsbSerialPort
-        if(usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() > 1)
-            return; // write buffer size detection unreliable as baud rate to high
+        assertEquals("write packet size", usb.writePacketSize, writePacketSize);
+        if (usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() == 1)  // write buffer size detection is unreliable
+            assertTrue("write buffer size " + writeBufferSize, writeBufferSize == usb.writeBufferSize || writeBufferSize == usb.writeBufferSize + 64);
+        else
+            assertEquals("write buffer size", usb.writeBufferSize, writeBufferSize);
+    }

+    @Test
+    public void writeTimeout() throws Exception {
+        // serial processing to slow for tests below, but they anyway only check shared code in CommonUsbSerialPort
+        Assume.assumeFalse(usb.serialDriver instanceof CdcAcmSerialDriver);
+        // write buffer size detection unreliable as baud rate to high
+        Assume.assumeFalse(usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() > 1);
+
+        usb.open();
        usb.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
        telnet.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
        TestBuffer tbuf;
+        int purgeTimeout = 250;

        // total write timeout
-        tbuf = new TestBuffer(writeBufferSize + writePacketSize);
-        int timeout = writePacketSize / 32 * 50; // time for 1.5 packets. write 48 byte in 50 msec at 9600 baud
-        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(writePacketSize);
+        tbuf = new TestBuffer(usb.writeBufferSize + usb.writePacketSize);
+        int timeout = usb.writePacketSize / 32 * 50; // time for 1.5 packets. write 48 byte in 50 msec at 9600 baud
        usb.serialPort.write(tbuf.buf, timeout);
        purgeWriteBuffer(purgeTimeout);
-        tbuf = new TestBuffer(writeBufferSize + 2*writePacketSize);
+        tbuf = new TestBuffer(usb.writeBufferSize + 2*usb.writePacketSize);
        try {
            usb.serialPort.write(tbuf.buf, timeout); // would not fail if each block has own timeout
            fail("write error expected");
@ -894,12 +923,11 @@ public class DeviceTest {
        purgeWriteBuffer(purgeTimeout);

        // infinite wait
-        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(writePacketSize);
        usb.serialPort.write(tbuf.buf, 0);
        purgeWriteBuffer(purgeTimeout);

        // timeout in bulkTransfer + SerialTimeoutException.bytesTransferred
-        int readWait = writePacketSize > 64 ? 250 : 50;
+        int readWait = usb.writePacketSize > 64 ? 250 : 50;
        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(tbuf.buf.length);
        try {
            usb.serialPort.write(tbuf.buf, timeout);
@ -911,10 +939,10 @@ public class DeviceTest {
                tbuf.testRead(data);
            }
            assertEquals(0, ex.bytesTransferred);
-            assertEquals(writeBufferSize + writePacketSize, tbuf.len);
+            assertEquals(usb.writeBufferSize + usb.writePacketSize, tbuf.len);
        }
        purgeWriteBuffer(purgeTimeout);
-        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(writePacketSize);
+        ((CommonUsbSerialPort)usb.serialPort).setWriteBufferSize(-1);
        tbuf.len = 0;
        try {
            usb.serialPort.write(tbuf.buf, timeout);
@ -925,8 +953,8 @@ public class DeviceTest {
                       data = telnet.read(-1, readWait)) {
                tbuf.testRead(data);
            }
-            assertEquals(writeBufferSize + writePacketSize, ex.bytesTransferred);
-            assertEquals(writeBufferSize + writePacketSize, tbuf.len);
+            assertEquals(usb.writeBufferSize + usb.writePacketSize, ex.bytesTransferred);
+            assertEquals(usb.writeBufferSize + usb.writePacketSize, tbuf.len);
        }
        purgeWriteBuffer(purgeTimeout);

@ -967,15 +995,12 @@ public class DeviceTest {
        if(usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() == 1)
            purge = false; // purge is blocking

-        int[] writeSizes = getWriteSizes();
-        int writePacketSize = writeSizes[0];
-        int writeBufferSize = writeSizes[1];
        int purgeTimeout = 250;
        TestBuffer tbuf;
        long begin;
        int duration1, duration2, retries, i;
        retries = purge ? 10 : 1;
-        tbuf = new TestBuffer(writeBufferSize);
+        tbuf = new TestBuffer(usb.writeBufferSize);

        ((CommonUsbSerialPort) usb.serialPort).setWriteBufferSize(tbuf.buf.length);
        Log.d(TAG, "writeDuration: full write begin");
@ -989,7 +1014,7 @@ public class DeviceTest {
        if(!purge)
            purgeWriteBuffer(purgeTimeout);
        Log.d(TAG, "writeDuration: full write end, duration " + duration1/(float)(retries) + " msec");
-        ((CommonUsbSerialPort) usb.serialPort).setWriteBufferSize(writePacketSize);
+        ((CommonUsbSerialPort) usb.serialPort).setWriteBufferSize(-1);
        Log.d(TAG, "writeDuration: packet write begin");
        begin = System.currentTimeMillis();
        for(i=0; i<retries; i++) {
@ -1010,7 +1035,7 @@ public class DeviceTest {
        usb.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
        telnet.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);

-        ((CommonUsbSerialPort) usb.serialPort).setWriteBufferSize(12);
+        ((CommonUsbSerialPort) usb.serialPort).setWriteBufferSize(12); // init buffer
        ((CommonUsbSerialPort) usb.serialPort).setWriteBufferSize(12); // keeps last buffer
        TestBuffer buf = new TestBuffer(256);
        usb.serialPort.write(buf.buf, 5000);
@ -1039,16 +1064,16 @@ public class DeviceTest {

        telnet.write("1aaa".getBytes());
        data = usb.read(4);
-        Assert.assertThat(data, equalTo("1aaa".getBytes()));
+        assertThat(data, equalTo("1aaa".getBytes()));
        telnet.write(new byte[16]);
        try {
            data = usb.read(16);
            if (usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() == 1)
-                Assert.assertNotEquals(0, data.length); // can be shorter or full length
+                assertNotEquals(0, data.length); // can be shorter or full length
            else if (usb.serialDriver instanceof ProlificSerialDriver)
-                Assert.assertTrue("expected > 0 and < 16 byte, got " + data.length, data.length > 0 && data.length < 16);
+                assertTrue("expected > 0 and < 16 byte, got " + data.length, data.length > 0 && data.length < 16);
            else // ftdi, ch340, cp2105
-                Assert.assertEquals(0, data.length);
+                assertEquals(0, data.length);
        } catch (IOException ignored) {
        }
        if (purge) {
@ -1085,18 +1110,18 @@ public class DeviceTest {
        
        telnet.write("2aaa".getBytes());
        data = usb.read(4, 8);
-        Assert.assertThat(data, equalTo("2aaa".getBytes()));
+        assertThat(data, equalTo("2aaa".getBytes()));
        telnet.write(new byte[16]);
        data = usb.read(16, 8);
        if (usb.serialDriver instanceof Cp21xxSerialDriver && usb.serialDriver.getPorts().size() == 1)
-            Assert.assertNotEquals(0, data.length); // can be shorter or full length
+            assertNotEquals(0, data.length); // can be shorter or full length
        else if (usb.serialDriver instanceof ProlificSerialDriver)
-            Assert.assertTrue("sporadic issue! expected > 0 and < 16 byte, got " + data.length, data.length > 0 && data.length < 16);
+            assertTrue("sporadic issue! expected > 0 and < 16 byte, got " + data.length, data.length > 0 && data.length < 16);
        else // ftdi, ch340, cp2105
-            Assert.assertEquals(0, data.length);
+            assertEquals(0, data.length);
        telnet.write("2ccc".getBytes());
        data = usb.read(4);
-        // Assert.assertThat(data, equalTo("1ccc".getBytes())); // unpredictable here. typically '2ccc' but sometimes '' or byte[16]
+        // assertThat(data, equalTo("1ccc".getBytes())); // unpredictable here. typically '2ccc' but sometimes '' or byte[16]
        if(data.length != 4) {
            if (purge) {
                usb.serialPort.purgeHwBuffers(true, true);
@ -1291,7 +1316,7 @@ public class DeviceTest {
    @Test
    public void purgeHwBuffers() throws Exception {
        // purge write buffer
-        // 2400 is slowest baud rate for isCp21xxRestrictedPort
+        // 2400 is slowest baud rate for usb.isCp21xxRestrictedPort
        usb.open();
        usb.setParameters(2400, 8, 1, UsbSerialPort.PARITY_NONE);
        telnet.setParameters(2400, 8, 1, UsbSerialPort.PARITY_NONE);
@ -1338,7 +1363,7 @@ public class DeviceTest {
        Thread.sleep(10); // ~ 20 bytes
        if(purged) {
            if(usb.serialDriver instanceof Cp21xxSerialDriver) { // only working on some devices/ports
-                if(isCp21xxRestrictedPort) {
+                if(usb.isCp21xxRestrictedPort) {
                    assertThat(usb.read(2), equalTo("xy".getBytes())); // cp2105/1
                } else if(usb.serialDriver.getPorts().size() > 1) {
                    assertThat(usb.read(1), equalTo("y".getBytes()));  // cp2105/0
@ -1506,6 +1531,23 @@ public class DeviceTest {
        data = telnet.read(2);
        assertEquals(2, data.length);
        usb.ioManager.setReadTimeout(200);
+
+        // with internal SerialTimeoutException
+        TestBuffer tbuf = new TestBuffer(usb.writeBufferSize + 2*usb.writePacketSize);
+        byte[] pbuf1 = new byte[tbuf.buf.length - 4];
+        byte[] pbuf2 = new byte[1];
+        System.arraycopy(tbuf.buf, 0,pbuf1, 0, pbuf1.length);
+        usb.ioManager.setWriteTimeout(20); // tbuf len >= 128, needs 133msec @ 9600 baud
+        usb.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
+        telnet.setParameters(9600, 8, 1, UsbSerialPort.PARITY_NONE);
+        usb.ioManager.writeAsync(pbuf1);
+        for(int i = pbuf1.length; i < tbuf.buf.length; i++) {
+            Thread.sleep(20);
+            pbuf2[0] = tbuf.buf[i];
+            usb.ioManager.writeAsync(pbuf2);
+        }
+        while(!tbuf.testRead(telnet.read(-1)))
+            ;
    }

    @Test
@ -1549,7 +1591,7 @@ public class DeviceTest {
        telnet.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);

        int longTimeout = 1000;
-        int shortTimeout = 10;
+        int shortTimeout = 20;
        time = System.currentTimeMillis();
        len = usb.serialPort.read(readBuf, shortTimeout);
        assertEquals(0, len);
@ -1602,15 +1644,10 @@ public class DeviceTest {

    @Test
    public void wrongDriver() throws Exception {
-
-        UsbDeviceConnection wrongDeviceConnection;
-        UsbSerialDriver wrongSerialDriver;
-        UsbSerialPort wrongSerialPort;
-
        if(!(usb.serialDriver instanceof CdcAcmSerialDriver)) {
-            wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
-            wrongSerialDriver = new CdcAcmSerialDriver(usb.serialDriver.getDevice());
-            wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new CdcAcmSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
            try {
                wrongSerialPort.open(wrongDeviceConnection);
                wrongSerialPort.setParameters(115200, UsbSerialPort.DATABITS_8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE); // ch340 fails here
@ -1631,9 +1668,9 @@ public class DeviceTest {
            }
        }
        if(!(usb.serialDriver instanceof Ch34xSerialDriver)) {
-            wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
-            wrongSerialDriver = new Ch34xSerialDriver(usb.serialDriver.getDevice());
-            wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new Ch34xSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
            try {
                wrongSerialPort.open(wrongDeviceConnection);
                fail("error expected");
@ -1647,9 +1684,9 @@ public class DeviceTest {
        }
        // FTDI only recovers from Cp21xx control commands with power toggle, so skip this combination!
        if(!(usb.serialDriver instanceof Cp21xxSerialDriver | usb.serialDriver instanceof FtdiSerialDriver)) {
-            wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
-            wrongSerialDriver = new Cp21xxSerialDriver(usb.serialDriver.getDevice());
-            wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new Cp21xxSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
            try {
                wrongSerialPort.open(wrongDeviceConnection);
                //if(usb.usbSerialDriver instanceof FtdiSerialDriver)
@ -1665,9 +1702,9 @@ public class DeviceTest {
            }
        }
        if(!(usb.serialDriver instanceof FtdiSerialDriver)) {
-            wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
-            wrongSerialDriver = new FtdiSerialDriver(usb.serialDriver.getDevice());
-            wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new FtdiSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
            try {
                wrongSerialPort.open(wrongDeviceConnection);
                if(usb.serialDriver instanceof Cp21xxSerialDriver)
@ -1683,9 +1720,9 @@ public class DeviceTest {
            }
        }
        if(!(usb.serialDriver instanceof ProlificSerialDriver)) {
-            wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
-            wrongSerialDriver = new ProlificSerialDriver(usb.serialDriver.getDevice());
-            wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new ProlificSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
            try {
                wrongSerialPort.open(wrongDeviceConnection);
                fail("error expected");
@ -1697,6 +1734,40 @@ public class DeviceTest {
            } catch (IOException ignored) {
            }
        }
+        if(!(usb.serialDriver instanceof GsmModemSerialDriver)) {
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new GsmModemSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            try {
+                wrongSerialPort.open(wrongDeviceConnection);
+            } catch (IOException ignored) {
+            }
+            assertEquals(usb.serialDriver.getDevice(), wrongSerialDriver.getDevice());
+            assertEquals(wrongSerialDriver, wrongSerialPort.getDriver());
+            assertThrows(UnsupportedOperationException.class, () -> wrongSerialPort.setParameters(9200, 8, 1, 0));
+            assertEquals(EnumSet.noneOf(ControlLine.class), wrongSerialPort.getSupportedControlLines());
+            try {
+                wrongSerialPort.close();
+            } catch (IOException ignored) {
+            }
+        }
+        if(!(usb.serialDriver instanceof ChromeCcdSerialDriver)) {
+            UsbDeviceConnection wrongDeviceConnection = usbManager.openDevice(usb.serialDriver.getDevice());
+            UsbSerialDriver wrongSerialDriver = new ChromeCcdSerialDriver(usb.serialDriver.getDevice());
+            UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+            try {
+                wrongSerialPort.open(wrongDeviceConnection);
+            } catch (IOException ignored) {
+            }
+            assertEquals(usb.serialDriver.getDevice(), wrongSerialDriver.getDevice());
+            assertEquals(wrongSerialDriver, wrongSerialPort.getDriver());
+            assertThrows(UnsupportedOperationException.class, () -> wrongSerialPort.setParameters(9200, 8, 1, 0));
+            assertEquals(EnumSet.noneOf(ControlLine.class), wrongSerialPort.getSupportedControlLines());
+            try {
+                wrongSerialPort.close();
+            } catch (IOException ignored) {
+            }
+        }
        // test that device recovers from wrong commands
        usb.open();
        telnet.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
@ -1726,40 +1797,19 @@ public class DeviceTest {
        byte[] data;
        int sleep = 10;

-        // output lines are supported by all drivers
-        // input lines are supported by all drivers except CDC
-        boolean inputLinesSupported = false;
-        boolean inputLinesConnected = false;
-        boolean onlyRtsCts = false;
-        if (usb.serialDriver instanceof FtdiSerialDriver) {
-            inputLinesSupported = true;
-            if(usb.serialDriver.getDevice().getProductId() == UsbId.FTDI_FT2232H)
-                inputLinesConnected = true; // I only have 74LS138 connected at FT2232, not at FT232
-            if(usb.serialDriver.getDevice().getProductId() == UsbId.FTDI_FT231X) {
-                inputLinesConnected = true;
-                onlyRtsCts = true; // I only test with FT230X that has only these 2 control lines. DTR is silently ignored
-            }
-        } else if (usb.serialDriver instanceof Cp21xxSerialDriver) {
-            inputLinesSupported = true;
-            if(usb.serialDriver.getPorts().size() == 1)
-                inputLinesConnected = true; // I only have 74LS138 connected at CP2102, not at CP2105
-        } else if (usb.serialDriver instanceof ProlificSerialDriver) {
-            inputLinesSupported = true;
-            inputLinesConnected = true;
-        } else if (usb.serialDriver instanceof Ch34xSerialDriver) {
-            inputLinesSupported = true;
-            if(usb.serialDriver.getDevice().getProductId() == UsbId.QINHENG_CH340)
-                inputLinesConnected = true;  // I only have 74LS138 connected at CH230, not connected at CH341A
-        }
-        Boolean inputLineFalse = inputLinesSupported ? Boolean.FALSE : null;
-        Boolean inputLineTrue = inputLinesConnected ? Boolean.TRUE : inputLineFalse;
+        Boolean inputLineFalse = usb.inputLinesSupported ? Boolean.FALSE : null;
+        Boolean inputLineTrue = usb.inputLinesConnected ? Boolean.TRUE : inputLineFalse;

-        EnumSet<UsbSerialPort.ControlLine> supportedControlLines = EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.DTR);
-        if(inputLinesSupported) {
-            supportedControlLines.add(UsbSerialPort.ControlLine.CTS);
-            supportedControlLines.add(UsbSerialPort.ControlLine.DSR);
-            supportedControlLines.add(UsbSerialPort.ControlLine.CD);
-            supportedControlLines.add(UsbSerialPort.ControlLine.RI);
+        EnumSet<ControlLine> supportedControlLines = EnumSet.noneOf(ControlLine.class);
+        if(usb.outputLinesSupported) {
+            supportedControlLines.add(ControlLine.RTS);
+            supportedControlLines.add(ControlLine.DTR);
+        }
+        if(usb.inputLinesSupported) {
+            supportedControlLines.add(ControlLine.CTS);
+            supportedControlLines.add(ControlLine.DSR);
+            supportedControlLines.add(ControlLine.CD);
+            supportedControlLines.add(ControlLine.RI);
        }

        // UsbSerialProber creates new UsbSerialPort objects which resets control lines,
@ -1771,19 +1821,29 @@ public class DeviceTest {
        Thread.sleep(sleep);

        assertEquals(supportedControlLines, usb.serialPort.getSupportedControlLines());
+        if(supportedControlLines == EnumSet.noneOf(ControlLine.class)) {
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getControlLines());
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getRTS());
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getCTS());
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getDTR());
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getDSR());
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getCD());
+            assertThrows(UnsupportedOperationException.class, () -> usb.serialPort.getRI());
+            return;
+        }

        // control lines reset on initial open
        data = "none".getBytes();
-        assertEquals(inputLinesConnected && !onlyRtsCts
-                        ? EnumSet.of(UsbSerialPort.ControlLine.RI)
-                        : EnumSet.noneOf(UsbSerialPort.ControlLine.class),
+        assertEquals(usb.inputLinesConnected && !usb.inputLinesOnlyRtsCts
+                        ? EnumSet.of(ControlLine.RI)
+                        : EnumSet.noneOf(ControlLine.class),
                usb.serialPort.getControlLines());
        assertThat(usb.getControlLine(usb.serialPort::getRTS), equalTo(Boolean.FALSE));
        assertThat(usb.getControlLine(usb.serialPort::getCTS), equalTo(inputLineFalse));
        assertThat(usb.getControlLine(usb.serialPort::getDTR), equalTo(Boolean.FALSE));
        assertThat(usb.getControlLine(usb.serialPort::getDSR), equalTo(inputLineFalse));
        assertThat(usb.getControlLine(usb.serialPort::getCD), equalTo(inputLineFalse));
-        assertThat(usb.getControlLine(usb.serialPort::getRI), equalTo(onlyRtsCts ? Boolean.FALSE : inputLineTrue));
+        assertThat(usb.getControlLine(usb.serialPort::getRI), equalTo(usb.inputLinesOnlyRtsCts ? Boolean.FALSE : inputLineTrue));
        telnet.write(data);
        if(usb.serialDriver instanceof CdcAcmSerialDriver)
            // arduino: control line feedback as serial_state notification is not implemented.
@ -1797,9 +1857,9 @@ public class DeviceTest {
        data = "rts ".getBytes();
        usb.serialPort.setRTS(true);
        Thread.sleep(sleep);
-        assertEquals(inputLinesConnected
-                        ? EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.CTS)
-                        : EnumSet.of(UsbSerialPort.ControlLine.RTS),
+        assertEquals(usb.inputLinesConnected
+                        ? EnumSet.of(ControlLine.RTS, ControlLine.CTS)
+                        : EnumSet.of(ControlLine.RTS),
                usb.serialPort.getControlLines());
        assertThat(usb.getControlLine(usb.serialPort::getRTS), equalTo(Boolean.TRUE));
        assertThat(usb.getControlLine(usb.serialPort::getCTS), equalTo(inputLineTrue));
@ -1815,17 +1875,17 @@ public class DeviceTest {
        data = "both".getBytes();
        usb.serialPort.setDTR(true);
        Thread.sleep(sleep);
-        assertEquals(onlyRtsCts
-                ? EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.DTR, UsbSerialPort.ControlLine.CTS)
-                : inputLinesConnected
-                ? EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.DTR, UsbSerialPort.ControlLine.CD)
-                : EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.DTR),
+        assertEquals(usb.inputLinesOnlyRtsCts
+                ? EnumSet.of(ControlLine.RTS, ControlLine.DTR, ControlLine.CTS)
+                : usb.inputLinesConnected
+                ? EnumSet.of(ControlLine.RTS, ControlLine.DTR, ControlLine.CD)
+                : EnumSet.of(ControlLine.RTS, ControlLine.DTR),
                usb.serialPort.getControlLines());
        assertThat(usb.getControlLine(usb.serialPort::getRTS), equalTo(Boolean.TRUE));
-        assertThat(usb.getControlLine(usb.serialPort::getCTS), equalTo(onlyRtsCts ? Boolean.TRUE : inputLineFalse));
+        assertThat(usb.getControlLine(usb.serialPort::getCTS), equalTo(usb.inputLinesOnlyRtsCts ? Boolean.TRUE : inputLineFalse));
        assertThat(usb.getControlLine(usb.serialPort::getDTR), equalTo(Boolean.TRUE));
        assertThat(usb.getControlLine(usb.serialPort::getDSR), equalTo(inputLineFalse));
-        assertThat(usb.getControlLine(usb.serialPort::getCD), equalTo(onlyRtsCts ? Boolean.FALSE : inputLineTrue));
+        assertThat(usb.getControlLine(usb.serialPort::getCD), equalTo(usb.inputLinesOnlyRtsCts ? Boolean.FALSE : inputLineTrue));
        assertThat(usb.getControlLine(usb.serialPort::getRI), equalTo(inputLineFalse));
        telnet.write(data);
        assertThat(Arrays.toString(data), usb.read(4), equalTo(data));
@ -1835,14 +1895,14 @@ public class DeviceTest {
        data = "dtr ".getBytes();
        usb.serialPort.setRTS(false);
        Thread.sleep(sleep);
-        assertEquals(inputLinesConnected && !onlyRtsCts
-                        ? EnumSet.of(UsbSerialPort.ControlLine.DTR, UsbSerialPort.ControlLine.DSR)
-                        : EnumSet.of(UsbSerialPort.ControlLine.DTR),
+        assertEquals(usb.inputLinesConnected && !usb.inputLinesOnlyRtsCts
+                        ? EnumSet.of(ControlLine.DTR, ControlLine.DSR)
+                        : EnumSet.of(ControlLine.DTR),
                usb.serialPort.getControlLines());
        assertThat(usb.getControlLine(usb.serialPort::getRTS), equalTo(Boolean.FALSE));
        assertThat(usb.getControlLine(usb.serialPort::getCTS), equalTo(inputLineFalse));
        assertThat(usb.getControlLine(usb.serialPort::getDTR), equalTo(Boolean.TRUE));
-        assertThat(usb.getControlLine(usb.serialPort::getDSR), equalTo(onlyRtsCts ? Boolean.FALSE : inputLineTrue));
+        assertThat(usb.getControlLine(usb.serialPort::getDSR), equalTo(usb.inputLinesOnlyRtsCts ? Boolean.FALSE : inputLineTrue));
        assertThat(usb.getControlLine(usb.serialPort::getCD), equalTo(inputLineFalse));
        assertThat(usb.getControlLine(usb.serialPort::getRI), equalTo(inputLineFalse));
        telnet.write(data);
@ -1851,7 +1911,7 @@ public class DeviceTest {
        assertThat(Arrays.toString(data), telnet.read(4), equalTo(data));

        // control lines retained over close+open
-        boolean inputRetained = inputLinesConnected;
+        boolean inputRetained = usb.inputLinesConnected;
        boolean outputRetained = true;
        usb.serialPort.setRTS(true);
        usb.serialPort.setDTR(false);
@ -1859,9 +1919,9 @@ public class DeviceTest {
        usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
        usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);

-        EnumSet<UsbSerialPort.ControlLine> retainedControlLines = EnumSet.noneOf(UsbSerialPort.ControlLine.class);
-        if(outputRetained) retainedControlLines.add(UsbSerialPort.ControlLine.RTS);
-        if(inputRetained)  retainedControlLines.add(UsbSerialPort.ControlLine.CTS);
+        EnumSet<ControlLine> retainedControlLines = EnumSet.noneOf(ControlLine.class);
+        if(outputRetained) retainedControlLines.add(ControlLine.RTS);
+        if(inputRetained)  retainedControlLines.add(ControlLine.CTS);
        assertEquals(retainedControlLines, usb.serialPort.getControlLines());
        assertThat(usb.getControlLine(usb.serialPort::getRTS), equalTo(outputRetained));
        assertThat(usb.getControlLine(usb.serialPort::getCTS), equalTo(inputRetained ? inputLineTrue : inputLineFalse));
@ -1875,25 +1935,25 @@ public class DeviceTest {
            usb.serialPort.setDTR(false);
            usb.close(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT));
            usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
-            assertEquals(EnumSet.of(UsbSerialPort.ControlLine.RI), usb.serialPort.getControlLines());
+            assertEquals(EnumSet.of(ControlLine.RI), usb.serialPort.getControlLines());

            usb.serialPort.setRTS(true);
            usb.serialPort.setDTR(false);
            usb.close(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT));
            usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
-            assertEquals(EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.CTS), usb.serialPort.getControlLines());
+            assertEquals(EnumSet.of(ControlLine.RTS, ControlLine.CTS), usb.serialPort.getControlLines());

            usb.serialPort.setRTS(false);
            usb.serialPort.setDTR(true);
            usb.close(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT));
            usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
-            assertEquals(EnumSet.of(UsbSerialPort.ControlLine.DTR, UsbSerialPort.ControlLine.DSR), usb.serialPort.getControlLines());
+            assertEquals(EnumSet.of(ControlLine.DTR, ControlLine.DSR), usb.serialPort.getControlLines());

            usb.serialPort.setRTS(true);
            usb.serialPort.setDTR(true);
            usb.close(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT));
            usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_CONTROL_LINE_INIT, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
-            assertEquals(EnumSet.of(UsbSerialPort.ControlLine.RTS, UsbSerialPort.ControlLine.DTR, UsbSerialPort.ControlLine.CD), usb.serialPort.getControlLines());
+            assertEquals(EnumSet.of(ControlLine.RTS, ControlLine.DTR, ControlLine.CD), usb.serialPort.getControlLines());
        }

        // force error
@ -1944,7 +2004,7 @@ public class DeviceTest {
        if (usb.serialDriver instanceof CdcAcmSerialDriver) {
            // BREAK forwarding not implemented by arduino_leonardo_bridge.ino
            assertThat("<break>", data, equalTo(new byte[]{}));
-        } else if(isCp21xxRestrictedPort) {
+        } else if(usb.isCp21xxRestrictedPort) {
            assertThat("<break>", data, equalTo(new byte[]{0x26})); // send the last byte again?
        } else {
            assertThat("<break>", data, equalTo(new byte[]{0}));
@ -2030,7 +2090,7 @@ public class DeviceTest {
            fail("setBreak error expected");
        } catch (IOException ignored) {
        }
-        usb.close();
+        usb.close(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_DEVICE_CONNECTION));
        try {
            usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD, UsbWrapper.OpenCloseFlags.NO_DEVICE_CONNECTION));
            fail("open error expected");
@ -2051,7 +2111,9 @@ public class DeviceTest {
    public void commonMethods() throws Exception {
        String s;
        assertNotNull(usb.serialPort.getDriver());
+        assertEquals(usb.serialDriver, usb.serialPort.getDriver());
        assertNotNull(usb.serialPort.getDevice());
+        assertEquals(usb.serialDriver.getDevice(), usb.serialPort.getDevice());
        assertEquals(test_device_port, usb.serialPort.getPortNumber());
        s = usb.serialDriver.toString();
        assertNotEquals(0, s.length());
@ -2060,8 +2122,6 @@ public class DeviceTest {
        usb.open();
        assertTrue(usb.serialPort.isOpen());

-        assertEquals(usb.serialPort.getWriteEndpoint().getMaxPacketSize(),
-                     usb.serialPort.getReadEndpoint().getMaxPacketSize());
        s = usb.serialPort.getSerial();
        // with target sdk 29 can throw SecurityException before USB permission dialog is confirmed
        // not all devices implement serial numbers. some observed values are:
@ -2084,6 +2144,26 @@ public class DeviceTest {
            usb.serialPort.read(buffer, UsbWrapper.USB_READ_WAIT);
            fail("read buffer to small expected");
        } catch(IllegalArgumentException ignored) {}
+        try {
+            byte[] buffer = new byte[1];
+            usb.serialPort.read(buffer, 0, UsbWrapper.USB_READ_WAIT);
+            fail("read length to small expected");
+        } catch(IllegalArgumentException ignored) {}
+
+        // use driver that does not override base class
+        UsbSerialDriver wrongSerialDriver = new ChromeCcdSerialDriver(usb.serialDriver.getDevice());
+        UsbSerialPort wrongSerialPort = wrongSerialDriver.getPorts().get(0);
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getCD);
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getCTS);
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getDSR);
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getDTR);
+        assertThrows(UnsupportedOperationException.class, () -> wrongSerialPort.setDTR(true));
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getRI);
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getRTS);
+        assertThrows(UnsupportedOperationException.class, () -> wrongSerialPort.setRTS(true));
+        assertThrows(UnsupportedOperationException.class, wrongSerialPort::getControlLines);
+        assertThrows(UnsupportedOperationException.class, () -> wrongSerialPort.purgeHwBuffers(true, true));
+        assertThrows(UnsupportedOperationException.class, () -> wrongSerialPort.setBreak(true));
    }

    @Test
@ -2110,7 +2190,7 @@ public class DeviceTest {
        long t3 = System.currentTimeMillis();
        ftdiSerialPort.setLatencyTimer(lt);
        assertTrue("latency 1: expected < 100, got "+ (t2-t1), (t2-t1) < 100);
-        assertTrue("latency 100: expected > 100, got " + (t3-t2), (t3-t2) > 100);
+        assertTrue("latency 100: expected >= 100, got " + (t3-t2), (t3-t2) >= 100);

        usb.deviceConnection.close();
        try {
--- a/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/CommonUsbSerialPortWrapper.java
+++ b/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/CommonUsbSerialPortWrapper.java
@ -0,0 +1,8 @@
+package com.hoho.android.usbserial.driver;
+
+public class CommonUsbSerialPortWrapper {
+    public static byte[] getWriteBuffer(UsbSerialPort serialPort) {
+        CommonUsbSerialPort commonSerialPort = (CommonUsbSerialPort) serialPort;
+        return commonSerialPort.mWriteBuffer;
+    }
+}
--- a/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/ProlificSerialPortWrapper.java
+++ b/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/ProlificSerialPortWrapper.java
@ -1,6 +1,6 @@
 package com.hoho.android.usbserial.driver;

-public class ProlificWrapper {
+public class ProlificSerialPortWrapper {
    public static boolean isDeviceTypeT(UsbSerialPort serialPort) {
        ProlificSerialDriver.ProlificSerialPort prolificSerialPort = (ProlificSerialDriver.ProlificSerialPort) serialPort;
        return prolificSerialPort.mDeviceType == ProlificSerialDriver.DeviceType.DEVICE_TYPE_T;
--- a/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/TestBuffer.java
+++ b/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/TestBuffer.java
@ -0,0 +1,32 @@
+package com.hoho.android.usbserial.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+public class TestBuffer {
+    public final byte[] buf;
+    public int len;
+
+    public TestBuffer(int length) {
+        len = 0;
+        buf = new byte[length];
+        int i = 0;
+        int j = 0;
+        for (j = 0; j < length / 16; j++)
+            for (int k = 0; k < 16; k++)
+                buf[i++] = (byte) j;
+        while (i < length)
+            buf[i++] = (byte) j;
+    }
+
+    public boolean testRead(byte[] data) {
+        assertNotEquals(0, data.length);
+        assertTrue("got " + (len + data.length) + " bytes", (len + data.length) <= buf.length);
+        for (int j = 0; j < data.length; j++)
+            assertEquals("at pos " + (len + j), (byte) ((len + j) / 16), data[j]);
+        len += data.length;
+        //Log.d(TAG, "read " + len);
+        return len == buf.length;
+    }
+}
--- a/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/UsbWrapper.java
+++ b/usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/UsbWrapper.java
@ -9,9 +9,16 @@ import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbManager;
 import android.media.RingtoneManager;
 import android.net.Uri;
+import android.os.Build;
 import android.util.Log;

 import com.hoho.android.usbserial.driver.CdcAcmSerialDriver;
+import com.hoho.android.usbserial.driver.Ch34xSerialDriver;
+import com.hoho.android.usbserial.driver.CommonUsbSerialPort;
+import com.hoho.android.usbserial.driver.Cp21xxSerialDriver;
+import com.hoho.android.usbserial.driver.FtdiSerialDriver;
+import com.hoho.android.usbserial.driver.ProlificSerialDriver;
+import com.hoho.android.usbserial.driver.UsbId;
 import com.hoho.android.usbserial.driver.UsbSerialDriver;
 import com.hoho.android.usbserial.driver.UsbSerialPort;

@ -47,12 +54,21 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
    public boolean readBlock = false;
    long readTime = 0;

+    // device properties
+    public boolean isCp21xxRestrictedPort; // second port of Cp2105 has limited dataBits, stopBits, parity
+    public boolean outputLinesSupported;
+    public boolean inputLinesSupported;
+    public boolean inputLinesConnected;
+    public boolean inputLinesOnlyRtsCts;
+    public int writePacketSize = -1;
+    public int writeBufferSize = -1;

    public UsbWrapper(Context context, UsbSerialDriver serialDriver, int devicePort) {
        this.context = context;
        this.serialDriver = serialDriver;
        this.devicePort = devicePort;
        serialPort = serialDriver.getPorts().get(devicePort);
+        CommonUsbSerialPort.DEBUG = true;
    }

    public void setUp() throws Exception {
@ -69,17 +85,70 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
                    granted[0] = intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false);
                }
            };
-            PendingIntent permissionIntent = PendingIntent.getBroadcast(context, 0, new Intent("com.android.example.USB_PERMISSION"), 0);
+            int flags = Build.VERSION.SDK_INT >= Build.VERSION_CODES.M ? PendingIntent.FLAG_MUTABLE : 0;
+            Intent intent = new Intent("com.android.example.USB_PERMISSION");
+            intent.setPackage(context.getPackageName());
+            PendingIntent permissionIntent = PendingIntent.getBroadcast(context, 0, intent, flags);
            IntentFilter filter = new IntentFilter("com.android.example.USB_PERMISSION");
-            context.registerReceiver(usbReceiver, filter);
+            context.registerReceiver(usbReceiver, filter, Context.RECEIVER_NOT_EXPORTED);
            usbManager.requestPermission(serialDriver.getDevice(), permissionIntent);
            for(int i=0; i<5000; i++) {
                if(granted[0] != null) break;
                Thread.sleep(1);
            }
            Log.d(TAG,"USB permission "+granted[0]);
-            assertTrue("USB permission dialog not confirmed", granted[0]==null?false:granted[0]);
+            assertTrue("USB permission dialog not confirmed", granted[0] != null && granted[0]);
        }
+
+        // extract some device properties:
+        isCp21xxRestrictedPort = serialDriver instanceof Cp21xxSerialDriver && serialDriver.getPorts().size()==2 && serialPort.getPortNumber() == 1;
+        // output lines are supported by all common drivers
+        // input lines are supported by all common drivers except CDC
+        if (serialDriver instanceof FtdiSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            if(serialDriver.getDevice().getProductId() == UsbId.FTDI_FT2232H)
+                inputLinesConnected = true; // I only have 74LS138 connected at FT2232, not at FT232
+            if(serialDriver.getDevice().getProductId() == UsbId.FTDI_FT231X) {
+                inputLinesConnected = true;
+                inputLinesOnlyRtsCts = true; // I only test with FT230X that has only these 2 control lines. DTR is silently ignored
+            }
+        } else if (serialDriver instanceof Cp21xxSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            if(serialDriver.getPorts().size() == 1)
+                inputLinesConnected = true; // I only have 74LS138 connected at CP2102, not at CP2105
+        } else if (serialDriver instanceof ProlificSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            inputLinesConnected = true;
+        } else if (serialDriver instanceof Ch34xSerialDriver) {
+            outputLinesSupported = true;
+            inputLinesSupported = true;
+            if(serialDriver.getDevice().getProductId() == UsbId.QINHENG_CH340)
+                inputLinesConnected = true;  // I only have 74LS138 connected at CH340, not connected at CH341A
+        } else if (serialDriver instanceof CdcAcmSerialDriver) {
+            outputLinesSupported = true;
+        }
+
+        if (serialDriver instanceof Cp21xxSerialDriver) {
+            if (serialDriver.getPorts().size() == 1) { writePacketSize = 64; writeBufferSize = 576; }
+            else if (serialPort.getPortNumber() == 0) { writePacketSize = 64; writeBufferSize = 320; }
+            else { writePacketSize = 32; writeBufferSize = 128; }; //, 160}; // write buffer size detection is unreliable
+        } else if (serialDriver instanceof Ch34xSerialDriver) {
+            writePacketSize = 32; writeBufferSize = 64;
+        } else if (serialDriver instanceof ProlificSerialDriver) {
+            writePacketSize = 64; writeBufferSize = 256;
+        } else if (serialDriver instanceof FtdiSerialDriver) {
+            switch (serialDriver.getPorts().size()) {
+                case 1: writePacketSize = 64; writeBufferSize = 128; break;
+                case 2: writePacketSize = 512; writeBufferSize = 4096; break;
+                case 4: writePacketSize = 512; writeBufferSize = 2048; break;
+            }
+        } else if (serialDriver instanceof CdcAcmSerialDriver) {
+            writePacketSize = 64; writeBufferSize = 128;
+        }
+
    }

    public void tearDown() {
@ -244,15 +313,40 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
        }
    }

+    // return [write packet size, write buffer size(s)]
+    public int[] getWriteSizes() {
+        if (serialDriver instanceof Cp21xxSerialDriver) {
+            if (serialDriver.getPorts().size() == 1) return new int[]{64, 576};
+            else if (serialPort.getPortNumber() == 0) return new int[]{64, 320};
+            else return new int[]{32, 128, 160}; // write buffer size detection is unreliable
+        } else if (serialDriver instanceof Ch34xSerialDriver) {
+            return new int[]{32, 64};
+        } else if (serialDriver instanceof ProlificSerialDriver) {
+            return new int[]{64, 256};
+        } else if (serialDriver instanceof FtdiSerialDriver) {
+            switch (serialDriver.getPorts().size()) {
+                case 1: return new int[]{64, 128};
+                case 2: return new int[]{512, 4096};
+                case 4: return new int[]{512, 2048};
+                default: return null;
+            }
+        } else if (serialDriver instanceof CdcAcmSerialDriver) {
+            return new int[]{64, 128};
+        } else {
+            return null;
+        }
+    }
+
+
    @Override
    public void onNewData(byte[] data) {
        long now = System.currentTimeMillis();
        if(readTime == 0)
            readTime = now;
        if(data.length > 64) {
-            Log.d(TAG, "usb read: time+=" + String.format("%-3d",now- readTime) + " len=" + String.format("%-4d",data.length) + " data=" + new String(data, 0, 32) + "..." + new String(data, data.length-32, 32));
+            Log.d(TAG, "usb " + devicePort + " read: time+=" + String.format("%-3d",now- readTime) + " len=" + String.format("%-4d",data.length) + " data=" + new String(data, 0, 32) + "..." + new String(data, data.length-32, 32));
        } else {
-            Log.d(TAG, "usb read: time+=" + String.format("%-3d",now- readTime) + " len=" + String.format("%-4d",data.length) + " data=" + new String(data));
+            Log.d(TAG, "usb " + devicePort + " read: time+=" + String.format("%-3d",now- readTime) + " len=" + String.format("%-4d",data.length) + " data=" + new String(data));
        }
        readTime = now;

--- a/usbSerialForAndroid/src/main/AndroidManifest.xml
+++ b/usbSerialForAndroid/src/main/AndroidManifest.xml
@ -1,4 +1,3 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-      package="com.hoho.android.usbserial">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
 </manifest>
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriver.java
@ -8,11 +8,13 @@ package com.hoho.android.usbserial.driver;

 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
 import android.util.Log;

+import com.hoho.android.usbserial.util.HexDump;
+import com.hoho.android.usbserial.util.UsbUtils;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.EnumSet;
@ -30,6 +32,8 @@ import java.util.Map;
 */
 public class CdcAcmSerialDriver implements UsbSerialDriver {

+    public static final int USB_SUBCLASS_ACM = 2;
+
    private final String TAG = CdcAcmSerialDriver.class.getSimpleName();

    private final UsbDevice mDevice;
@ -38,23 +42,33 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
    public CdcAcmSerialDriver(UsbDevice device) {
        mDevice = device;
        mPorts = new ArrayList<>();
-
-        int controlInterfaceCount = 0;
-        int dataInterfaceCount = 0;
-        for( int i = 0; i < device.getInterfaceCount(); i++) {
-            if(device.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_COMM)
-                controlInterfaceCount++;
-            if(device.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA)
-                dataInterfaceCount++;
-        }
-        for( int port = 0; port < Math.min(controlInterfaceCount, dataInterfaceCount); port++) {
+        int ports = countPorts(device);
+        for (int port = 0; port < ports; port++) {
            mPorts.add(new CdcAcmSerialPort(mDevice, port));
        }
-        if(mPorts.size() == 0) {
+        if (mPorts.size() == 0) {
            mPorts.add(new CdcAcmSerialPort(mDevice, -1));
        }
    }

+    @SuppressWarnings({"unused"})
+    public static boolean probe(UsbDevice device) {
+        return countPorts(device) > 0;
+    }
+
+    private static int countPorts(UsbDevice device) {
+        int controlInterfaceCount = 0;
+        int dataInterfaceCount = 0;
+        for (int i = 0; i < device.getInterfaceCount(); i++) {
+            if (device.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_COMM &&
+                    device.getInterface(i).getInterfaceSubclass() == USB_SUBCLASS_ACM)
+                controlInterfaceCount++;
+            if (device.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA)
+                dataInterfaceCount++;
+        }
+        return Math.min(controlInterfaceCount, dataInterfaceCount);
+    }
+
    @Override
    public UsbDevice getDevice() {
        return mDevice;
@ -95,7 +109,11 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
        }

        @Override
-        protected void openInt(UsbDeviceConnection connection) throws IOException {
+        protected void openInt() throws IOException {
+            Log.d(TAG, "interfaces:");
+            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                Log.d(TAG, mDevice.getInterface(i).toString());
+            }
            if (mPortNumber == -1) {
                Log.d(TAG,"device might be castrated ACM device, trying single interface logic");
                openSingleInterface();
@ -131,38 +149,57 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
        }

        private void openInterface() throws IOException {
-            Log.d(TAG, "claiming interfaces, count=" + mDevice.getInterfaceCount());

-            int controlInterfaceCount = 0;
-            int dataInterfaceCount = 0;
            mControlInterface = null;
            mDataInterface = null;
-            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
-                UsbInterface usbInterface = mDevice.getInterface(i);
-                if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_COMM) {
-                    if(controlInterfaceCount == mPortNumber) {
-                        mControlIndex = i;
-                        mControlInterface = usbInterface;
+            int j = getInterfaceIdFromDescriptors();
+            Log.d(TAG, "interface count=" + mDevice.getInterfaceCount() + ", IAD=" + j);
+            if (j >= 0) {
+                for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                    UsbInterface usbInterface = mDevice.getInterface(i);
+                    if (usbInterface.getId() == j || usbInterface.getId() == j+1) {
+                        if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_COMM &&
+                                usbInterface.getInterfaceSubclass() == USB_SUBCLASS_ACM) {
+                            mControlIndex = usbInterface.getId();
+                            mControlInterface = usbInterface;
+                        }
+                        if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
+                            mDataInterface = usbInterface;
+                        }
                    }
-                    controlInterfaceCount++;
                }
-                if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
-                    if(dataInterfaceCount == mPortNumber) {
-                        mDataInterface = usbInterface;
+            }
+            if (mControlInterface == null || mDataInterface == null) {
+                Log.d(TAG, "no IAD fallback");
+                int controlInterfaceCount = 0;
+                int dataInterfaceCount = 0;
+                for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                    UsbInterface usbInterface = mDevice.getInterface(i);
+                    if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_COMM &&
+                            usbInterface.getInterfaceSubclass() == USB_SUBCLASS_ACM) {
+                        if (controlInterfaceCount == mPortNumber) {
+                            mControlIndex = usbInterface.getId();
+                            mControlInterface = usbInterface;
+                        }
+                        controlInterfaceCount++;
+                    }
+                    if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
+                        if (dataInterfaceCount == mPortNumber) {
+                            mDataInterface = usbInterface;
+                        }
+                        dataInterfaceCount++;
                    }
-                    dataInterfaceCount++;
                }
            }

            if(mControlInterface == null) {
                throw new IOException("No control interface");
            }
-            Log.d(TAG, "Control iface=" + mControlInterface);
+            Log.d(TAG, "Control interface id " + mControlInterface.getId());

            if (!mConnection.claimInterface(mControlInterface, true)) {
                throw new IOException("Could not claim control interface");
            }
-
            mControlEndpoint = mControlInterface.getEndpoint(0);
            if (mControlEndpoint.getDirection() != UsbConstants.USB_DIR_IN || mControlEndpoint.getType() != UsbConstants.USB_ENDPOINT_XFER_INT) {
                throw new IOException("Invalid control endpoint");
@ -171,12 +208,10 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
            if(mDataInterface == null) {
                throw new IOException("No data interface");
            }
-            Log.d(TAG, "data iface=" + mDataInterface);
-
+            Log.d(TAG, "data interface id " + mDataInterface.getId());
            if (!mConnection.claimInterface(mDataInterface, true)) {
                throw new IOException("Could not claim data interface");
            }
-
            for (int i = 0; i < mDataInterface.getEndpointCount(); i++) {
                UsbEndpoint ep = mDataInterface.getEndpoint(i);
                if (ep.getDirection() == UsbConstants.USB_DIR_IN && ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
@ -186,6 +221,36 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
            }
        }

+        private int getInterfaceIdFromDescriptors() {
+            ArrayList<byte[]> descriptors = UsbUtils.getDescriptors(mConnection);
+            Log.d(TAG, "USB descriptor:");
+            for(byte[] descriptor : descriptors)
+                Log.d(TAG, HexDump.toHexString(descriptor));
+
+            if (descriptors.size() > 0 &&
+                    descriptors.get(0).length == 18 &&
+                    descriptors.get(0)[1] == 1 && // bDescriptorType
+                    descriptors.get(0)[4] == (byte)(UsbConstants.USB_CLASS_MISC) && //bDeviceClass
+                    descriptors.get(0)[5] == 2 && // bDeviceSubClass
+                    descriptors.get(0)[6] == 1) { // bDeviceProtocol
+                // is IAD device, see https://www.usb.org/sites/default/files/iadclasscode_r10.pdf
+                int port = -1;
+                for (int d = 1; d < descriptors.size(); d++) {
+                    if (descriptors.get(d).length == 8 &&
+                            descriptors.get(d)[1] == 0x0b && // bDescriptorType == IAD
+                            descriptors.get(d)[4] == UsbConstants.USB_CLASS_COMM && // bFunctionClass == CDC
+                            descriptors.get(d)[5] == USB_SUBCLASS_ACM) { // bFunctionSubClass == ACM
+                        port++;
+                        if (port == mPortNumber &&
+                                descriptors.get(d)[3] == 2) { // bInterfaceCount
+                            return descriptors.get(d)[2]; // bFirstInterface
+                        }
+                    }
+                }
+            }
+            return -1;
+        }
+
        private int sendAcmControlMessage(int request, int value, byte[] buf) throws IOException {
            int len = mConnection.controlTransfer(
                    USB_RT_ACM, request, value, mControlIndex, buf, buf != null ? buf.length : 0, 5000);
@ -286,42 +351,9 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {

    }

+    @SuppressWarnings({"unused"})
    public static Map<Integer, int[]> getSupportedDevices() {
-        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
-        supportedDevices.put(UsbId.VENDOR_ARDUINO,
-                new int[] {
-                        UsbId.ARDUINO_UNO,
-                        UsbId.ARDUINO_UNO_R3,
-                        UsbId.ARDUINO_MEGA_2560,
-                        UsbId.ARDUINO_MEGA_2560_R3,
-                        UsbId.ARDUINO_SERIAL_ADAPTER,
-                        UsbId.ARDUINO_SERIAL_ADAPTER_R3,
-                        UsbId.ARDUINO_MEGA_ADK,
-                        UsbId.ARDUINO_MEGA_ADK_R3,
-                        UsbId.ARDUINO_LEONARDO,
-                        UsbId.ARDUINO_MICRO,
-                });
-        supportedDevices.put(UsbId.VENDOR_VAN_OOIJEN_TECH,
-                new int[] {
-                    UsbId.VAN_OOIJEN_TECH_TEENSYDUINO_SERIAL,
-                });
-        supportedDevices.put(UsbId.VENDOR_ATMEL,
-                new int[] {
-                    UsbId.ATMEL_LUFA_CDC_DEMO_APP,
-                });
-        supportedDevices.put(UsbId.VENDOR_LEAFLABS,
-                new int[] {
-                    UsbId.LEAFLABS_MAPLE,
-                });
-        supportedDevices.put(UsbId.VENDOR_ARM,
-                new int[] {
-                    UsbId.ARM_MBED,
-                });
-        supportedDevices.put(UsbId.VENDOR_ST,
-                new int[] {
-                        UsbId.ST_CDC,
-                });
-        return supportedDevices;
+        return new LinkedHashMap<>();
    }

 }
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Ch34xSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Ch34xSerialDriver.java
@ -7,7 +7,6 @@ package com.hoho.android.usbserial.driver;

 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
 import android.util.Log;
@ -23,365 +22,366 @@ import java.util.Map;

 public class Ch34xSerialDriver implements UsbSerialDriver {

-	private static final String TAG = Ch34xSerialDriver.class.getSimpleName();
+    private static final String TAG = Ch34xSerialDriver.class.getSimpleName();

-	private final UsbDevice mDevice;
-	private final UsbSerialPort mPort;
+    private final UsbDevice mDevice;
+    private final UsbSerialPort mPort;

-	private static final int LCR_ENABLE_RX   = 0x80;
-	private static final int LCR_ENABLE_TX   = 0x40;
-	private static final int LCR_MARK_SPACE  = 0x20;
-	private static final int LCR_PAR_EVEN    = 0x10;
-	private static final int LCR_ENABLE_PAR  = 0x08;
-	private static final int LCR_STOP_BITS_2 = 0x04;
-	private static final int LCR_CS8         = 0x03;
-	private static final int LCR_CS7         = 0x02;
-	private static final int LCR_CS6         = 0x01;
-	private static final int LCR_CS5         = 0x00;
+    private static final int LCR_ENABLE_RX   = 0x80;
+    private static final int LCR_ENABLE_TX   = 0x40;
+    private static final int LCR_MARK_SPACE  = 0x20;
+    private static final int LCR_PAR_EVEN    = 0x10;
+    private static final int LCR_ENABLE_PAR  = 0x08;
+    private static final int LCR_STOP_BITS_2 = 0x04;
+    private static final int LCR_CS8         = 0x03;
+    private static final int LCR_CS7         = 0x02;
+    private static final int LCR_CS6         = 0x01;
+    private static final int LCR_CS5         = 0x00;

-	private static final int GCL_CTS = 0x01;
-	private static final int GCL_DSR = 0x02;
-	private static final int GCL_RI  = 0x04;
-	private static final int GCL_CD  = 0x08;
-	private static final int SCL_DTR = 0x20;
-	private static final int SCL_RTS = 0x40;
+    private static final int GCL_CTS = 0x01;
+    private static final int GCL_DSR = 0x02;
+    private static final int GCL_RI  = 0x04;
+    private static final int GCL_CD  = 0x08;
+    private static final int SCL_DTR = 0x20;
+    private static final int SCL_RTS = 0x40;

-	public Ch34xSerialDriver(UsbDevice device) {
-		mDevice = device;
-		mPort = new Ch340SerialPort(mDevice, 0);
-	}
+    public Ch34xSerialDriver(UsbDevice device) {
+        mDevice = device;
+        mPort = new Ch340SerialPort(mDevice, 0);
+    }

-	@Override
-	public UsbDevice getDevice() {
-		return mDevice;
-	}
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }

-	@Override
-	public List<UsbSerialPort> getPorts() {
-		return Collections.singletonList(mPort);
-	}
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return Collections.singletonList(mPort);
+    }

-	public class Ch340SerialPort extends CommonUsbSerialPort {
+    public class Ch340SerialPort extends CommonUsbSerialPort {

-		private static final int USB_TIMEOUT_MILLIS = 5000;
+        private static final int USB_TIMEOUT_MILLIS = 5000;

-		private final int DEFAULT_BAUD_RATE = 9600;
+        private final int DEFAULT_BAUD_RATE = 9600;

-		private boolean dtr = false;
-		private boolean rts = false;
+        private boolean dtr = false;
+        private boolean rts = false;

-		public Ch340SerialPort(UsbDevice device, int portNumber) {
-			super(device, portNumber);
-		}
+        public Ch340SerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }

-		@Override
-		public UsbSerialDriver getDriver() {
-			return Ch34xSerialDriver.this;
-		}
+        @Override
+        public UsbSerialDriver getDriver() {
+            return Ch34xSerialDriver.this;
+        }

-		@Override
-		protected void openInt(UsbDeviceConnection connection) throws IOException {
-			for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
-				UsbInterface usbIface = mDevice.getInterface(i);
-				if (!mConnection.claimInterface(usbIface, true)) {
-					throw new IOException("Could not claim data interface");
-				}
-			}
+        @Override
+        protected void openInt() throws IOException {
+            for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
+                UsbInterface usbIface = mDevice.getInterface(i);
+                if (!mConnection.claimInterface(usbIface, true)) {
+                    throw new IOException("Could not claim data interface");
+                }
+            }

-			UsbInterface dataIface = mDevice.getInterface(mDevice.getInterfaceCount() - 1);
-			for (int i = 0; i < dataIface.getEndpointCount(); i++) {
-				UsbEndpoint ep = dataIface.getEndpoint(i);
-				if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
-					if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
-						mReadEndpoint = ep;
-					} else {
-						mWriteEndpoint = ep;
-					}
-				}
-			}
+            UsbInterface dataIface = mDevice.getInterface(mDevice.getInterfaceCount() - 1);
+            for (int i = 0; i < dataIface.getEndpointCount(); i++) {
+                UsbEndpoint ep = dataIface.getEndpoint(i);
+                if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
+                    if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
+                        mReadEndpoint = ep;
+                    } else {
+                        mWriteEndpoint = ep;
+                    }
+                }
+            }

-			initialize();
-			setBaudRate(DEFAULT_BAUD_RATE);
-		}
+            initialize();
+            setBaudRate(DEFAULT_BAUD_RATE);
+        }

-		@Override
-		protected void closeInt() {
-			try {
-				for (int i = 0; i < mDevice.getInterfaceCount(); i++)
-					mConnection.releaseInterface(mDevice.getInterface(i));
-			} catch(Exception ignored) {}
-		}
+        @Override
+        protected void closeInt() {
+            try {
+                for (int i = 0; i < mDevice.getInterfaceCount(); i++)
+                    mConnection.releaseInterface(mDevice.getInterface(i));
+            } catch(Exception ignored) {}
+        }

-		private int controlOut(int request, int value, int index) {
-			final int REQTYPE_HOST_TO_DEVICE = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_OUT;
-			return mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request,
-					value, index, null, 0, USB_TIMEOUT_MILLIS);
-		}
+        private int controlOut(int request, int value, int index) {
+            final int REQTYPE_HOST_TO_DEVICE = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_OUT;
+            return mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, request,
+                    value, index, null, 0, USB_TIMEOUT_MILLIS);
+        }


-		private int controlIn(int request, int value, int index, byte[] buffer) {
-			final int REQTYPE_DEVICE_TO_HOST = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_IN;
-			return mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, request,
-					value, index, buffer, buffer.length, USB_TIMEOUT_MILLIS);
-		}
+        private int controlIn(int request, int value, int index, byte[] buffer) {
+            final int REQTYPE_DEVICE_TO_HOST = UsbConstants.USB_TYPE_VENDOR | UsbConstants.USB_DIR_IN;
+            return mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, request,
+                    value, index, buffer, buffer.length, USB_TIMEOUT_MILLIS);
+        }


-		private void checkState(String msg, int request, int value, int[] expected) throws IOException {
-			byte[] buffer = new byte[expected.length];
-			int ret = controlIn(request, value, 0, buffer);
+        private void checkState(String msg, int request, int value, int[] expected) throws IOException {
+            byte[] buffer = new byte[expected.length];
+            int ret = controlIn(request, value, 0, buffer);

-			if (ret < 0) {
-				throw new IOException("Failed send cmd [" + msg + "]");
-			}
+            if (ret < 0) {
+                throw new IOException("Failed send cmd [" + msg + "]");
+            }

-			if (ret != expected.length) {
-				throw new IOException("Expected " + expected.length + " bytes, but get " + ret + " [" + msg + "]");
-			}
+            if (ret != expected.length) {
+                throw new IOException("Expected " + expected.length + " bytes, but get " + ret + " [" + msg + "]");
+            }

-			for (int i = 0; i < expected.length; i++) {
-				if (expected[i] == -1) {
-					continue;
-				}
+            for (int i = 0; i < expected.length; i++) {
+                if (expected[i] == -1) {
+                    continue;
+                }

-				int current = buffer[i] & 0xff;
-				if (expected[i] != current) {
-					throw new IOException("Expected 0x" + Integer.toHexString(expected[i]) + " byte, but get 0x" + Integer.toHexString(current) + " [" + msg + "]");
-				}
-			}
-		}
+                int current = buffer[i] & 0xff;
+                if (expected[i] != current) {
+                    throw new IOException("Expected 0x" + Integer.toHexString(expected[i]) + " byte, but get 0x" + Integer.toHexString(current) + " [" + msg + "]");
+                }
+            }
+        }

-		private void setControlLines() throws IOException {
-			if (controlOut(0xa4, ~((dtr ? SCL_DTR : 0) | (rts ? SCL_RTS : 0)), 0) < 0) {
-				throw new IOException("Failed to set control lines");
-			}
-		}
+        private void setControlLines() throws IOException {
+            if (controlOut(0xa4, ~((dtr ? SCL_DTR : 0) | (rts ? SCL_RTS : 0)), 0) < 0) {
+                throw new IOException("Failed to set control lines");
+            }
+        }

-		private byte getStatus() throws IOException {
-			byte[] buffer = new byte[2];
-			int ret = controlIn(0x95, 0x0706, 0, buffer);
-			if (ret < 0)
-				throw new IOException("Error getting control lines");
-			return buffer[0];
-		}
+        private byte getStatus() throws IOException {
+            byte[] buffer = new byte[2];
+            int ret = controlIn(0x95, 0x0706, 0, buffer);
+            if (ret < 0)
+                throw new IOException("Error getting control lines");
+            return buffer[0];
+        }

-		private void initialize() throws IOException {
-			checkState("init #1", 0x5f, 0, new int[]{-1 /* 0x27, 0x30 */, 0x00});
+        private void initialize() throws IOException {
+            checkState("init #1", 0x5f, 0, new int[]{-1 /* 0x27, 0x30 */, 0x00});

-			if (controlOut(0xa1, 0, 0) < 0) {
-				throw new IOException("Init failed: #2");
-			}
+            if (controlOut(0xa1, 0, 0) < 0) {
+                throw new IOException("Init failed: #2");
+            }

-			setBaudRate(DEFAULT_BAUD_RATE);
+            setBaudRate(DEFAULT_BAUD_RATE);

-			checkState("init #4", 0x95, 0x2518, new int[]{-1 /* 0x56, c3*/, 0x00});
+            checkState("init #4", 0x95, 0x2518, new int[]{-1 /* 0x56, c3*/, 0x00});

-			if (controlOut(0x9a, 0x2518, LCR_ENABLE_RX | LCR_ENABLE_TX | LCR_CS8) < 0) {
-				throw new IOException("Init failed: #5");
-			}
+            if (controlOut(0x9a, 0x2518, LCR_ENABLE_RX | LCR_ENABLE_TX | LCR_CS8) < 0) {
+                throw new IOException("Init failed: #5");
+            }

-			checkState("init #6", 0x95, 0x0706, new int[]{-1/*0xf?*/, -1/*0xec,0xee*/});
+            checkState("init #6", 0x95, 0x0706, new int[]{-1/*0xf?*/, -1/*0xec,0xee*/});

-			if (controlOut(0xa1, 0x501f, 0xd90a) < 0) {
-				throw new IOException("Init failed: #7");
-			}
+            if (controlOut(0xa1, 0x501f, 0xd90a) < 0) {
+                throw new IOException("Init failed: #7");
+            }

-			setBaudRate(DEFAULT_BAUD_RATE);
+            setBaudRate(DEFAULT_BAUD_RATE);

-			setControlLines();
+            setControlLines();

-			checkState("init #10", 0x95, 0x0706, new int[]{-1/* 0x9f, 0xff*/, -1/*0xec,0xee*/});
-		}
+            checkState("init #10", 0x95, 0x0706, new int[]{-1/* 0x9f, 0xff*/, -1/*0xec,0xee*/});
+        }


-		private void setBaudRate(int baudRate) throws IOException {
-			long factor;
-			long divisor;
+        private void setBaudRate(int baudRate) throws IOException {
+            long factor;
+            long divisor;

-			if (baudRate == 921600) {
-				divisor = 7;
-				factor = 0xf300;
-			} else {
-				final long BAUDBASE_FACTOR = 1532620800;
-				final int BAUDBASE_DIVMAX = 3;
+            if (baudRate == 921600) {
+                divisor = 7;
+                factor = 0xf300;
+            } else {
+                final long BAUDBASE_FACTOR = 1532620800;
+                final int BAUDBASE_DIVMAX = 3;

-				if(BuildConfig.DEBUG && (baudRate & (3<<29)) == (1<<29))
-					baudRate &= ~(1<<29); // for testing purpose bypass dedicated baud rate handling
-				factor = BAUDBASE_FACTOR / baudRate;
-				divisor = BAUDBASE_DIVMAX;
-				while ((factor > 0xfff0) && divisor > 0) {
-					factor >>= 3;
-					divisor--;
-				}
-				if (factor > 0xfff0) {
-					throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
-				}
-				factor = 0x10000 - factor;
-			}
+                if(BuildConfig.DEBUG && (baudRate & (3<<29)) == (1<<29))
+                    baudRate &= ~(1<<29); // for testing purpose bypass dedicated baud rate handling
+                factor = BAUDBASE_FACTOR / baudRate;
+                divisor = BAUDBASE_DIVMAX;
+                while ((factor > 0xfff0) && divisor > 0) {
+                    factor >>= 3;
+                    divisor--;
+                }
+                if (factor > 0xfff0) {
+                    throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
+                }
+                factor = 0x10000 - factor;
+            }

-			divisor |= 0x0080; // else ch341a waits until buffer full
-			int val1 = (int) ((factor & 0xff00) | divisor);
-			int val2 = (int) (factor & 0xff);
-			Log.d(TAG, String.format("baud rate=%d, 0x1312=0x%04x, 0x0f2c=0x%04x", baudRate, val1, val2));
-			int ret = controlOut(0x9a, 0x1312, val1);
-			if (ret < 0) {
-				throw new IOException("Error setting baud rate: #1)");
-			}
-			ret = controlOut(0x9a, 0x0f2c, val2);
-			if (ret < 0) {
-				throw new IOException("Error setting baud rate: #2");
-			}
-		}
+            divisor |= 0x0080; // else ch341a waits until buffer full
+            int val1 = (int) ((factor & 0xff00) | divisor);
+            int val2 = (int) (factor & 0xff);
+            Log.d(TAG, String.format("baud rate=%d, 0x1312=0x%04x, 0x0f2c=0x%04x", baudRate, val1, val2));
+            int ret = controlOut(0x9a, 0x1312, val1);
+            if (ret < 0) {
+                throw new IOException("Error setting baud rate: #1)");
+            }
+            ret = controlOut(0x9a, 0x0f2c, val2);
+            if (ret < 0) {
+                throw new IOException("Error setting baud rate: #2");
+            }
+        }

-		@Override
-		public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
-			if(baudRate <= 0) {
-				throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
-			}
-			setBaudRate(baudRate);
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, @Parity int parity) throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
+            setBaudRate(baudRate);

-			int lcr = LCR_ENABLE_RX | LCR_ENABLE_TX;
+            int lcr = LCR_ENABLE_RX | LCR_ENABLE_TX;

-			switch (dataBits) {
-				case DATABITS_5:
-					lcr |= LCR_CS5;
-					break;
-				case DATABITS_6:
-					lcr |= LCR_CS6;
-					break;
-				case DATABITS_7:
-					lcr |= LCR_CS7;
-					break;
-				case DATABITS_8:
-					lcr |= LCR_CS8;
-					break;
-				default:
-					throw new IllegalArgumentException("Invalid data bits: " + dataBits);
-			}
+            switch (dataBits) {
+                case DATABITS_5:
+                    lcr |= LCR_CS5;
+                    break;
+                case DATABITS_6:
+                    lcr |= LCR_CS6;
+                    break;
+                case DATABITS_7:
+                    lcr |= LCR_CS7;
+                    break;
+                case DATABITS_8:
+                    lcr |= LCR_CS8;
+                    break;
+                default:
+                    throw new IllegalArgumentException("Invalid data bits: " + dataBits);
+            }

-			switch (parity) {
-				case PARITY_NONE:
-					break;
-				case PARITY_ODD:
-					lcr |= LCR_ENABLE_PAR;
-					break;
-				case PARITY_EVEN:
-					lcr |= LCR_ENABLE_PAR | LCR_PAR_EVEN;
-					break;
-				case PARITY_MARK:
-					lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE;
-					break;
-				case PARITY_SPACE:
-					lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE | LCR_PAR_EVEN;
-					break;
-				default:
-					throw new IllegalArgumentException("Invalid parity: " + parity);
-			}
+            switch (parity) {
+                case PARITY_NONE:
+                    break;
+                case PARITY_ODD:
+                    lcr |= LCR_ENABLE_PAR;
+                    break;
+                case PARITY_EVEN:
+                    lcr |= LCR_ENABLE_PAR | LCR_PAR_EVEN;
+                    break;
+                case PARITY_MARK:
+                    lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE;
+                    break;
+                case PARITY_SPACE:
+                    lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE | LCR_PAR_EVEN;
+                    break;
+                default:
+                    throw new IllegalArgumentException("Invalid parity: " + parity);
+            }

-			switch (stopBits) {
-				case STOPBITS_1:
-					break;
-				case STOPBITS_1_5:
-					throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
-				case STOPBITS_2:
-					lcr |= LCR_STOP_BITS_2;
-					break;
-				default:
-					throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
-			}
+            switch (stopBits) {
+                case STOPBITS_1:
+                    break;
+                case STOPBITS_1_5:
+                    throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
+                case STOPBITS_2:
+                    lcr |= LCR_STOP_BITS_2;
+                    break;
+                default:
+                    throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
+            }

-			int ret = controlOut(0x9a, 0x2518, lcr);
-			if (ret < 0) {
-				throw new IOException("Error setting control byte");
-			}
-		}
+            int ret = controlOut(0x9a, 0x2518, lcr);
+            if (ret < 0) {
+                throw new IOException("Error setting control byte");
+            }
+        }

-		@Override
-		public boolean getCD() throws IOException {
-			return (getStatus() & GCL_CD) == 0;
-		}
+        @Override
+        public boolean getCD() throws IOException {
+            return (getStatus() & GCL_CD) == 0;
+        }

-		@Override
-		public boolean getCTS() throws IOException {
-			return (getStatus() & GCL_CTS) == 0;
-		}
+        @Override
+        public boolean getCTS() throws IOException {
+            return (getStatus() & GCL_CTS) == 0;
+        }

-		@Override
-		public boolean getDSR() throws IOException {
-			return (getStatus() & GCL_DSR) == 0;
-		}
+        @Override
+        public boolean getDSR() throws IOException {
+            return (getStatus() & GCL_DSR) == 0;
+        }

-		@Override
-		public boolean getDTR() throws IOException {
-			return dtr;
-		}
+        @Override
+        public boolean getDTR() throws IOException {
+            return dtr;
+        }

-		@Override
-		public void setDTR(boolean value) throws IOException {
-			dtr = value;
-			setControlLines();
-		}
+        @Override
+        public void setDTR(boolean value) throws IOException {
+            dtr = value;
+            setControlLines();
+        }

-		@Override
-		public boolean getRI() throws IOException {
-			return (getStatus() & GCL_RI) == 0;
-		}
+        @Override
+        public boolean getRI() throws IOException {
+            return (getStatus() & GCL_RI) == 0;
+        }

-		@Override
-		public boolean getRTS() throws IOException {
-			return rts;
-		}
+        @Override
+        public boolean getRTS() throws IOException {
+            return rts;
+        }

-		@Override
-		public void setRTS(boolean value) throws IOException {
-			rts = value;
-			setControlLines();
-		}
+        @Override
+        public void setRTS(boolean value) throws IOException {
+            rts = value;
+            setControlLines();
+        }

-		@Override
-		public EnumSet<ControlLine> getControlLines() throws IOException {
-			int status = getStatus();
-			EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
-			if(rts) set.add(ControlLine.RTS);
-			if((status & GCL_CTS) == 0) set.add(ControlLine.CTS);
-			if(dtr) set.add(ControlLine.DTR);
-			if((status & GCL_DSR) == 0) set.add(ControlLine.DSR);
-			if((status & GCL_CD) == 0) set.add(ControlLine.CD);
-			if((status & GCL_RI) == 0) set.add(ControlLine.RI);
-			return set;
-		}
+        @Override
+        public EnumSet<ControlLine> getControlLines() throws IOException {
+            int status = getStatus();
+            EnumSet<ControlLine> set = EnumSet.noneOf(ControlLine.class);
+            if(rts) set.add(ControlLine.RTS);
+            if((status & GCL_CTS) == 0) set.add(ControlLine.CTS);
+            if(dtr) set.add(ControlLine.DTR);
+            if((status & GCL_DSR) == 0) set.add(ControlLine.DSR);
+            if((status & GCL_CD) == 0) set.add(ControlLine.CD);
+            if((status & GCL_RI) == 0) set.add(ControlLine.RI);
+            return set;
+        }

-		@Override
-		public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
-			return EnumSet.allOf(ControlLine.class);
-		}
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.allOf(ControlLine.class);
+        }

-		@Override
-		public void setBreak(boolean value) throws IOException {
-			byte[] req = new byte[2];
-			if(controlIn(0x95, 0x1805, 0, req) < 0) {
-				throw new IOException("Error getting BREAK condition");
-			}
-			if(value) {
-				req[0] &= ~1;
-				req[1] &= ~0x40;
-			} else {
-				req[0] |= 1;
-				req[1] |= 0x40;
-			}
-			int val = (req[1] & 0xff) << 8 | (req[0] & 0xff);
-			if(controlOut(0x9a, 0x1805, val) < 0) {
-				throw new IOException("Error setting BREAK condition");
-			}
-		}
-	}
+        @Override
+        public void setBreak(boolean value) throws IOException {
+            byte[] req = new byte[2];
+            if(controlIn(0x95, 0x1805, 0, req) < 0) {
+                throw new IOException("Error getting BREAK condition");
+            }
+            if(value) {
+                req[0] &= ~1;
+                req[1] &= ~0x40;
+            } else {
+                req[0] |= 1;
+                req[1] |= 0x40;
+            }
+            int val = (req[1] & 0xff) << 8 | (req[0] & 0xff);
+            if(controlOut(0x9a, 0x1805, val) < 0) {
+                throw new IOException("Error setting BREAK condition");
+            }
+        }
+    }

-	public static Map<Integer, int[]> getSupportedDevices() {
-		final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
-		supportedDevices.put(UsbId.VENDOR_QINHENG, new int[]{
-				UsbId.QINHENG_CH340,
-				UsbId.QINHENG_CH341A,
-		});
-		return supportedDevices;
-	}
+    @SuppressWarnings({"unused"})
+    public static Map<Integer, int[]> getSupportedDevices() {
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_QINHENG, new int[]{
+                UsbId.QINHENG_CH340,
+                UsbId.QINHENG_CH341A,
+        });
+        return supportedDevices;
+    }

 }
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ChromeCcdSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ChromeCcdSerialDriver.java
@ -0,0 +1,96 @@
+package com.hoho.android.usbserial.driver;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+import android.util.Log;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.ArrayList;
+
+public class ChromeCcdSerialDriver implements UsbSerialDriver{
+
+    private final String TAG = ChromeCcdSerialDriver.class.getSimpleName();
+
+    private final UsbDevice mDevice;
+    private final List<UsbSerialPort> mPorts;
+
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }
+
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return mPorts;
+    }
+
+    public ChromeCcdSerialDriver(UsbDevice mDevice) {
+        this.mDevice = mDevice;
+        mPorts = new ArrayList<UsbSerialPort>();
+        for (int i = 0; i < 3; i++)
+            mPorts.add(new ChromeCcdSerialPort(mDevice, i));
+    }
+
+    public class ChromeCcdSerialPort extends CommonUsbSerialPort {
+        private UsbInterface mDataInterface;
+
+        public ChromeCcdSerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }
+
+        @Override
+        protected void openInt() throws IOException {
+            Log.d(TAG, "claiming interfaces, count=" + mDevice.getInterfaceCount());
+            mDataInterface = mDevice.getInterface(mPortNumber);
+            if (!mConnection.claimInterface(mDataInterface, true)) {
+                throw new IOException("Could not claim shared control/data interface");
+            }
+            Log.d(TAG, "endpoint count=" + mDataInterface.getEndpointCount());
+            for (int i = 0; i < mDataInterface.getEndpointCount(); ++i) {
+                UsbEndpoint ep = mDataInterface.getEndpoint(i);
+                if ((ep.getDirection() == UsbConstants.USB_DIR_IN) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mReadEndpoint = ep;
+                } else if ((ep.getDirection() == UsbConstants.USB_DIR_OUT) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mWriteEndpoint = ep;
+                }
+            }
+        }
+
+        @Override
+        protected void closeInt() {
+            try {
+                mConnection.releaseInterface(mDataInterface);
+            } catch(Exception ignored) {}
+        }
+
+        @Override
+        public UsbSerialDriver getDriver() {
+            return ChromeCcdSerialDriver.this;
+        }
+
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.noneOf(ControlLine.class);
+        }
+    }
+
+    public static Map<Integer, int[]> getSupportedDevices() {
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_GOOGLE, new int[]{
+                UsbId.GOOGLE_CR50,
+        });
+        return supportedDevices;
+    }
+}
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CommonUsbSerialPort.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CommonUsbSerialPort.java
@ -25,28 +25,32 @@ import java.util.EnumSet;
 */
 public abstract class CommonUsbSerialPort implements UsbSerialPort {

+    public static boolean DEBUG = false;
+
    private static final String TAG = CommonUsbSerialPort.class.getSimpleName();
-    private static final int DEFAULT_WRITE_BUFFER_SIZE = 16 * 1024;
    private static final int MAX_READ_SIZE = 16 * 1024; // = old bulkTransfer limit

    protected final UsbDevice mDevice;
    protected final int mPortNumber;

    // non-null when open()
-    protected UsbDeviceConnection mConnection = null;
+    protected UsbDeviceConnection mConnection;
    protected UsbEndpoint mReadEndpoint;
    protected UsbEndpoint mWriteEndpoint;
    protected UsbRequest mUsbRequest;

-    protected final Object mWriteBufferLock = new Object();
-    /** Internal write buffer.  Guarded by {@link #mWriteBufferLock}. */
+    /**
+     * Internal write buffer.
+     *  Guarded by {@link #mWriteBufferLock}.
+     *  Default length = mReadEndpoint.getMaxPacketSize()
+     **/
    protected byte[] mWriteBuffer;
+    protected final Object mWriteBufferLock = new Object();
+

    public CommonUsbSerialPort(UsbDevice device, int portNumber) {
        mDevice = device;
        mPortNumber = portNumber;
-
-        mWriteBuffer = new byte[DEFAULT_WRITE_BUFFER_SIZE];
    }

    @Override
@ -85,11 +89,19 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
     * Sets the size of the internal buffer used to exchange data with the USB
     * stack for write operations.  Most users should not need to change this.
     *
-     * @param bufferSize the size in bytes
+     * @param bufferSize the size in bytes, <= 0 resets original size
     */
    public final void setWriteBufferSize(int bufferSize) {
        synchronized (mWriteBufferLock) {
-            if (bufferSize == mWriteBuffer.length) {
+            if (bufferSize <= 0) {
+                if (mWriteEndpoint != null) {
+                    bufferSize = mWriteEndpoint.getMaxPacketSize();
+                } else {
+                    mWriteBuffer = null;
+                    return;
+                }
+            }
+            if (mWriteBuffer != null && bufferSize == mWriteBuffer.length) {
                return;
            }
            mWriteBuffer = new byte[bufferSize];
@ -106,7 +118,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
        }
        mConnection = connection;
        try {
-            openInt(connection);
+            openInt();
            if (mReadEndpoint == null || mWriteEndpoint == null) {
                throw new IOException("Could not get read & write endpoints");
            }
@ -120,17 +132,18 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
        }
    }

-    protected abstract void openInt(UsbDeviceConnection connection) throws IOException;
+    protected abstract void openInt() throws IOException;

    @Override
    public void close() throws IOException {
        if (mConnection == null) {
            throw new IOException("Already closed");
        }
-        try {
-            mUsbRequest.cancel();
-        } catch(Exception ignored) {}
+        UsbRequest usbRequest = mUsbRequest;
        mUsbRequest = null;
+        try {
+            usbRequest.cancel();
+        } catch(Exception ignored) {}
        try {
            closeInt();
        } catch(Exception ignored) {}
@ -145,25 +158,40 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
    /**
     * use simple USB request supported by all devices to test if connection is still valid
     */
-    protected void testConnection() throws IOException {
+    protected void testConnection(boolean full) throws IOException {
+        testConnection(full, "USB get_status request failed");
+    }
+
+    protected void testConnection(boolean full, String msg) throws IOException {
+        if(mUsbRequest == null) {
+            throw new IOException("Connection closed");
+        }
+        if(!full) {
+            return;
+        }
        byte[] buf = new byte[2];
        int len = mConnection.controlTransfer(0x80 /*DEVICE*/, 0 /*GET_STATUS*/, 0, 0, buf, buf.length, 200);
        if(len < 0)
-            throw new IOException("USB get_status request failed");
+            throw new IOException(msg);
    }

    @Override
    public int read(final byte[] dest, final int timeout) throws IOException {
-        return read(dest, timeout, true);
+        if(dest.length == 0) {
+            throw new IllegalArgumentException("Read buffer too small");
+        }
+        return read(dest, dest.length, timeout);
    }

-    protected int read(final byte[] dest, final int timeout, boolean testConnection) throws IOException {
-        if(mConnection == null) {
-            throw new IOException("Connection closed");
-        }
-        if(dest.length <= 0) {
-            throw new IllegalArgumentException("Read buffer to small");
+    @Override
+    public int read(final byte[] dest, final int length, final int timeout) throws IOException {return read(dest, length, timeout, true);}
+
+    protected int read(final byte[] dest, int length, final int timeout, boolean testConnection) throws IOException {
+        testConnection(false);
+        if(length <= 0) {
+            throw new IllegalArgumentException("Read length too small");
        }
+        length = Math.min(length, dest.length);
        final int nread;
        if (timeout != 0) {
            // bulkTransfer will cause data loss with short timeout + high baud rates + continuous transfer
@ -175,16 +203,16 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
            //     /system/lib64/libandroid_runtime.so (android_hardware_UsbDeviceConnection_request_wait(_JNIEnv*, _jobject*, long)+84)
            // data loss / crashes were observed with timeout up to 200 msec
            long endTime = testConnection ? MonotonicClock.millis() + timeout : 0;
-            int readMax = Math.min(dest.length, MAX_READ_SIZE);
+            int readMax = Math.min(length, MAX_READ_SIZE);
            nread = mConnection.bulkTransfer(mReadEndpoint, dest, readMax, timeout);
            // Android error propagation is improvable:
            //  nread == -1 can be: timeout, connection lost, buffer to small, ???
-            if(nread == -1 && testConnection && MonotonicClock.millis() < endTime)
-                testConnection();
+            if(nread == -1 && testConnection)
+                testConnection(MonotonicClock.millis() < endTime);

        } else {
-            final ByteBuffer buf = ByteBuffer.wrap(dest);
-            if (!mUsbRequest.queue(buf, dest.length)) {
+            final ByteBuffer buf = ByteBuffer.wrap(dest, 0, length);
+            if (!mUsbRequest.queue(buf, length)) {
                throw new IOException("Queueing USB request failed");
            }
            final UsbRequest response = mConnection.requestWait();
@ -195,21 +223,23 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
            // Android error propagation is improvable:
            //   response != null & nread == 0 can be: connection lost, buffer to small, ???
            if(nread == 0) {
-                testConnection();
+                testConnection(true);
            }
        }
        return Math.max(nread, 0);
    }

    @Override
-    public void write(final byte[] src, final int timeout) throws IOException {
-        int offset = 0;
-        final long endTime = (timeout == 0) ? 0 : (MonotonicClock.millis() + timeout);
+    public void write(byte[] src, int timeout) throws IOException {write(src, src.length, timeout);}

-        if(mConnection == null) {
-            throw new IOException("Connection closed");
-        }
-        while (offset < src.length) {
+    @Override
+    public void write(final byte[] src, int length, final int timeout) throws IOException {
+        int offset = 0;
+        long startTime = MonotonicClock.millis();
+        length = Math.min(length, src.length);
+
+        testConnection(false);
+        while (offset < length) {
            int requestTimeout;
            final int requestLength;
            final int actualLength;
@ -217,7 +247,10 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
            synchronized (mWriteBufferLock) {
                final byte[] writeBuffer;

-                requestLength = Math.min(src.length - offset, mWriteBuffer.length);
+                if (mWriteBuffer == null) {
+                    mWriteBuffer = new byte[mWriteEndpoint.getMaxPacketSize()];
+                }
+                requestLength = Math.min(length - offset, mWriteBuffer.length);
                if (offset == 0) {
                    writeBuffer = src;
                } else {
@ -228,7 +261,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
                if (timeout == 0 || offset == 0) {
                    requestTimeout = timeout;
                } else {
-                    requestTimeout = (int)(endTime - MonotonicClock.millis());
+                    requestTimeout = (int)(startTime + timeout - MonotonicClock.millis());
                    if(requestTimeout == 0)
                        requestTimeout = -1;
                }
@ -238,14 +271,18 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
                    actualLength = mConnection.bulkTransfer(mWriteEndpoint, writeBuffer, requestLength, requestTimeout);
                }
            }
-            Log.d(TAG, "Wrote " + actualLength + "/" + requestLength + " offset " + offset + "/" + src.length + " timeout " + requestTimeout);
+            long elapsed = MonotonicClock.millis() - startTime;
+            if (DEBUG) {
+                Log.d(TAG, "Wrote " + actualLength + "/" + requestLength + " offset " + offset + "/" + length + " time " + elapsed + "/" + requestTimeout);
+            }
            if (actualLength <= 0) {
-                if (timeout != 0 && MonotonicClock.millis() >= endTime) {
-                    SerialTimeoutException ex = new SerialTimeoutException("Error writing " + requestLength + " bytes at offset " + offset + " of total " + src.length + ", rc=" + actualLength);
-                    ex.bytesTransferred = offset;
-                    throw ex;
+                String msg = "Error writing " + requestLength + " bytes at offset " + offset + " of total " + src.length + " after " + elapsed + "msec, rc=" + actualLength;
+                if (timeout != 0) {
+                    testConnection(elapsed < timeout, msg);
+                    throw new SerialTimeoutException(msg, offset);
                } else {
-                    throw new IOException("Error writing " + requestLength + " bytes at offset " + offset + " of total " + src.length);
+                    throw new IOException(msg);
+
                }
            }
            offset += actualLength;
@ -254,7 +291,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {

    @Override
    public boolean isOpen() {
-        return mConnection != null;
+        return mUsbRequest != null;
    }

    @Override
@ -285,7 +322,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
    public void setRTS(boolean value) throws IOException { throw new UnsupportedOperationException(); }

    @Override
-    public abstract EnumSet<ControlLine> getControlLines() throws IOException;
+    public EnumSet<ControlLine> getControlLines() throws IOException { throw new UnsupportedOperationException(); }

    @Override
    public abstract EnumSet<ControlLine> getSupportedControlLines() throws IOException;
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java
@ -8,7 +8,6 @@ package com.hoho.android.usbserial.driver;

 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;

@ -119,14 +118,14 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
            byte[] buffer = new byte[1];
            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, SILABSER_GET_MDMSTS_REQUEST_CODE, 0,
                    mPortNumber, buffer, buffer.length, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 1) {
+            if (result != buffer.length) {
                throw new IOException("Control transfer failed: " + SILABSER_GET_MDMSTS_REQUEST_CODE + " / " + 0 + " -> " + result);
            }
            return buffer[0];
        }

        @Override
-        protected void openInt(UsbDeviceConnection connection) throws IOException {
+        protected void openInt() throws IOException {
            mIsRestrictedPort = mDevice.getInterfaceCount() == 2 && mPortNumber == 1;
            if(mPortNumber >= mDevice.getInterfaceCount()) {
                throw new IOException("Unknown port number");
@ -321,6 +320,7 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
        }
    }

+    @SuppressWarnings({"unused"})
    public static Map<Integer, int[]> getSupportedDevices() {
        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
        supportedDevices.put(UsbId.VENDOR_SILABS,
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java
@ -9,7 +9,6 @@ package com.hoho.android.usbserial.driver;

 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.util.Log;

 import com.hoho.android.usbserial.util.MonotonicClock;
@ -99,8 +98,8 @@ public class FtdiSerialDriver implements UsbSerialDriver {


        @Override
-        protected void openInt(UsbDeviceConnection connection) throws IOException {
-            if (!connection.claimInterface(mDevice.getInterface(mPortNumber), true)) {
+        protected void openInt() throws IOException {
+            if (!mConnection.claimInterface(mDevice.getInterface(mPortNumber), true)) {
                throw new IOException("Could not claim interface " + mPortNumber);
            }
            if (mDevice.getInterface(mPortNumber).getEndpointCount() < 2) {
@ -123,7 +122,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
            }

            // mDevice.getVersion() would require API 23
-            byte[] rawDescriptors = connection.getRawDescriptors();
+            byte[] rawDescriptors = mConnection.getRawDescriptors();
            if(rawDescriptors == null || rawDescriptors.length < 14) {
                throw new IOException("Could not get device descriptors");
            }
@ -140,24 +139,37 @@ public class FtdiSerialDriver implements UsbSerialDriver {
        }

        @Override
-        public int read(final byte[] dest, final int timeout) throws IOException {
+        public int read(final byte[] dest, final int timeout) throws IOException
+        {
            if(dest.length <= READ_HEADER_LENGTH) {
-                throw new IllegalArgumentException("Read buffer to small");
+                throw new IllegalArgumentException("Read buffer too small");
                // could allocate larger buffer, including space for 2 header bytes, but this would
                // result in buffers not being 64 byte aligned any more, causing data loss at continuous
                // data transfer at high baud rates when buffers are fully filled.
            }
+            return read(dest, dest.length, timeout);
+        }
+
+        @Override
+        public int read(final byte[] dest, int length, final int timeout) throws IOException {
+            if(length <= READ_HEADER_LENGTH) {
+                throw new IllegalArgumentException("Read length too small");
+                // could allocate larger buffer, including space for 2 header bytes, but this would
+                // result in buffers not being 64 byte aligned any more, causing data loss at continuous
+                // data transfer at high baud rates when buffers are fully filled.
+            }
+            length = Math.min(length, dest.length);
            int nread;
            if (timeout != 0) {
                long endTime = MonotonicClock.millis() + timeout;
                do {
-                    nread = super.read(dest, Math.max(1, (int)(endTime - MonotonicClock.millis())), false);
+                    nread = super.read(dest, length, Math.max(1, (int)(endTime - MonotonicClock.millis())), false);
                } while (nread == READ_HEADER_LENGTH && MonotonicClock.millis() < endTime);
-                if(nread <= 0 && MonotonicClock.millis() < endTime)
-                    testConnection();
+                if(nread <= 0)
+                    testConnection(MonotonicClock.millis() < endTime);
            } else {
                do {
-                    nread = super.read(dest, timeout, false);
+                    nread = super.read(dest, length, timeout);
                } while (nread == READ_HEADER_LENGTH);
            }
            return readFilter(dest, nread);
@ -291,7 +303,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
            byte[] data = new byte[2];
            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, GET_MODEM_STATUS_REQUEST,
                    0, mPortNumber+1, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 2) {
+            if (result != data.length) {
                throw new IOException("Get modem status failed: result=" + result);
            }
            return data[0];
@ -407,7 +419,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
            byte[] data = new byte[1];
            int result = mConnection.controlTransfer(REQTYPE_DEVICE_TO_HOST, GET_LATENCY_TIMER_REQUEST,
                    0, mPortNumber+1, data, data.length, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 1) {
+            if (result != data.length) {
                throw new IOException("Get latency timer failed: result=" + result);
            }
            return data[0];
@ -415,6 +427,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {

    }

+    @SuppressWarnings({"unused"})
    public static Map<Integer, int[]> getSupportedDevices() {
        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
        supportedDevices.put(UsbId.VENDOR_FTDI,
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/GsmModemSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/GsmModemSerialDriver.java
@ -0,0 +1,106 @@
+package com.hoho.android.usbserial.driver;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+import android.util.Log;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+public class GsmModemSerialDriver implements UsbSerialDriver{
+
+    private final String TAG = GsmModemSerialDriver.class.getSimpleName();
+
+    private final UsbDevice mDevice;
+    private final UsbSerialPort mPort;
+
+    @Override
+    public UsbDevice getDevice() {
+        return mDevice;
+    }
+
+    @Override
+    public List<UsbSerialPort> getPorts() {
+        return Collections.singletonList(mPort);
+    }
+
+    public GsmModemSerialDriver(UsbDevice mDevice) {
+        this.mDevice = mDevice;
+        mPort = new GsmModemSerialPort(mDevice, 0);
+    }
+
+    public class GsmModemSerialPort extends CommonUsbSerialPort {
+
+        private UsbInterface mDataInterface;
+
+        public GsmModemSerialPort(UsbDevice device, int portNumber) {
+            super(device, portNumber);
+        }
+
+        @Override
+        protected void openInt() throws IOException {
+            Log.d(TAG, "claiming interfaces, count=" + mDevice.getInterfaceCount());
+            mDataInterface = mDevice.getInterface(0);
+            if (!mConnection.claimInterface(mDataInterface, true)) {
+                throw new IOException("Could not claim shared control/data interface");
+            }
+            Log.d(TAG, "endpoint count=" + mDataInterface.getEndpointCount());
+            for (int i = 0; i < mDataInterface.getEndpointCount(); ++i) {
+                UsbEndpoint ep = mDataInterface.getEndpoint(i);
+                if ((ep.getDirection() == UsbConstants.USB_DIR_IN) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mReadEndpoint = ep;
+                } else if ((ep.getDirection() == UsbConstants.USB_DIR_OUT) && (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)) {
+                    mWriteEndpoint = ep;
+                }
+            }
+            initGsmModem();
+        }
+
+        @Override
+        protected void closeInt() {
+            try {
+                mConnection.releaseInterface(mDataInterface);
+            } catch(Exception ignored) {}
+
+        }
+
+        private int initGsmModem() throws IOException {
+            int len = mConnection.controlTransfer(
+                    0x21, 0x22, 0x01, 0, null, 0, 5000);
+            if(len < 0) {
+                throw new IOException("init failed");
+            }
+            return len;
+        }
+
+        @Override
+        public UsbSerialDriver getDriver() {
+            return GsmModemSerialDriver.this;
+        }
+
+        @Override
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public EnumSet<ControlLine> getSupportedControlLines() throws IOException {
+            return EnumSet.noneOf(ControlLine.class);
+        }
+    }
+
+    public static Map<Integer, int[]> getSupportedDevices() {
+        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
+        supportedDevices.put(UsbId.VENDOR_UNISOC, new int[]{
+                UsbId.FIBOCOM_L610,
+                UsbId.FIBOCOM_L612,
+        });
+        return supportedDevices;
+    }
+}
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProbeTable.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProbeTable.java
@ -6,6 +6,7 @@

 package com.hoho.android.usbserial.driver;

+import android.hardware.usb.UsbDevice;
 import android.util.Pair;

 import java.lang.reflect.InvocationTargetException;
@ -14,14 +15,14 @@ import java.util.LinkedHashMap;
 import java.util.Map;

 /**
- * Maps (vendor id, product id) pairs to the corresponding serial driver.
- *
- * @author mike wakerly (opensource@hoho.com)
+ * Maps (vendor id, product id) pairs to the corresponding serial driver,
+ * or invoke 'probe' method to check actual USB devices for matching interfaces.
 */
 public class ProbeTable {

-    private final Map<Pair<Integer, Integer>, Class<? extends UsbSerialDriver>> mProbeTable =
+    private final Map<Pair<Integer, Integer>, Class<? extends UsbSerialDriver>> mVidPidProbeTable =
            new LinkedHashMap<>();
+    private final Map<Method, Class<? extends UsbSerialDriver>> mMethodProbeTable = new LinkedHashMap<>();

    /**
     * Adds or updates a (vendor, product) pair in the table.
@ -33,7 +34,7 @@ public class ProbeTable {
     */
    public ProbeTable addProduct(int vendorId, int productId,
            Class<? extends UsbSerialDriver> driverClass) {
-        mProbeTable.put(Pair.create(vendorId, productId), driverClass);
+        mVidPidProbeTable.put(Pair.create(vendorId, productId), driverClass);
        return this;
    }

@ -41,12 +42,11 @@ public class ProbeTable {
     * Internal method to add all supported products from
     * {@code getSupportedProducts} static method.
     *
-     * @param driverClass
-     * @return
+     * @param driverClass to be added
     */
    @SuppressWarnings("unchecked")
-    ProbeTable addDriver(Class<? extends UsbSerialDriver> driverClass) {
-        final Method method;
+    void addDriver(Class<? extends UsbSerialDriver> driverClass) {
+        Method method;

        try {
            method = driverClass.getMethod("getSupportedDevices");
@ -68,20 +68,35 @@ public class ProbeTable {
            }
        }

-        return this;
+        try {
+            method = driverClass.getMethod("probe", UsbDevice.class);
+            mMethodProbeTable.put(method, driverClass);
+        } catch (SecurityException | NoSuchMethodException ignored) {
+        }
    }

    /**
-     * Returns the driver for the given (vendor, product) pair, or {@code null}
-     * if no match.
+     * Returns the driver for the given USB device, or {@code null} if no match.
     *
-     * @param vendorId the USB vendor id
-     * @param productId the USB product id
+     * @param usbDevice the USB device to be probed
     * @return the driver class matching this pair, or {@code null}
     */
-    public Class<? extends UsbSerialDriver> findDriver(int vendorId, int productId) {
-        final Pair<Integer, Integer> pair = Pair.create(vendorId, productId);
-        return mProbeTable.get(pair);
+    public Class<? extends UsbSerialDriver> findDriver(final UsbDevice usbDevice) {
+        final Pair<Integer, Integer> pair = Pair.create(usbDevice.getVendorId(), usbDevice.getProductId());
+        Class<? extends UsbSerialDriver> driverClass = mVidPidProbeTable.get(pair);
+        if (driverClass != null)
+            return driverClass;
+        for (Map.Entry<Method, Class<? extends UsbSerialDriver>> entry : mMethodProbeTable.entrySet()) {
+            try {
+                Method method = entry.getKey();
+                Object o = method.invoke(null, usbDevice);
+                if((boolean)o)
+                    return entry.getValue();
+            } catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return null;
    }

 }
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProlificSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProlificSerialDriver.java
@ -11,7 +11,6 @@ package com.hoho.android.usbserial.driver;

 import android.hardware.usb.UsbConstants;
 import android.hardware.usb.UsbDevice;
-import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbEndpoint;
 import android.hardware.usb.UsbInterface;
 import android.util.Log;
@ -35,7 +34,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
            28800, 38400, 57600, 115200, 128000, 134400, 161280, 201600, 230400, 268800,
            403200, 460800, 614400, 806400, 921600, 1228800, 2457600, 3000000, 6000000
    };
-    protected enum DeviceType { DEVICE_TYPE_01, DEVICE_TYPE_T, DEVICE_TYPE_HX, DEVICE_TYPE_HXN}
+    protected enum DeviceType { DEVICE_TYPE_01, DEVICE_TYPE_T, DEVICE_TYPE_HX, DEVICE_TYPE_HXN }

    private final UsbDevice mDevice;
    private final UsbSerialPort mPort;
@ -123,7 +122,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
        private volatile Thread mReadStatusThread = null;
        private final Object mReadStatusThreadLock = new Object();
        private boolean mStopReadStatusThread = false;
-        private IOException mReadStatusException = null;
+        private Exception mReadStatusException = null;


        public ProlificSerialPort(UsbDevice device, int portNumber) {
@ -139,7 +138,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
            byte[] buffer = new byte[length];
            int result = mConnection.controlTransfer(requestType, request, value, index, buffer, length, USB_READ_TIMEOUT_MILLIS);
            if (result != length) {
-                throw new IOException(String.format("ControlTransfer 0x%x failed: %d",value, result));
+                throw new IOException(String.format("ControlTransfer %s 0x%x failed: %d",mDeviceType.name(), value, result));
            }
            return buffer;
        }
@ -148,7 +147,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
            int length = (data == null) ? 0 : data.length;
            int result = mConnection.controlTransfer(requestType, request, value, index, data, length, USB_WRITE_TIMEOUT_MILLIS);
            if (result != length) {
-                throw new IOException( String.format("ControlTransfer 0x%x failed: %d", value, result));
+                throw new IOException( String.format("ControlTransfer %s 0x%x failed: %d", mDeviceType.name(), value, result));
            }
        }

@ -202,12 +201,12 @@ public class ProlificSerialDriver implements UsbSerialDriver {

        private void readStatusThreadFunction() {
            try {
+                byte[] buffer = new byte[STATUS_BUFFER_SIZE];
                while (!mStopReadStatusThread) {
-                    byte[] buffer = new byte[STATUS_BUFFER_SIZE];
                    long endTime = MonotonicClock.millis() + 500;
                    int readBytesCount = mConnection.bulkTransfer(mInterruptEndpoint, buffer, STATUS_BUFFER_SIZE, 500);
-                    if(readBytesCount == -1 && MonotonicClock.millis() < endTime)
-                        testConnection();
+                    if(readBytesCount == -1)
+                        testConnection(MonotonicClock.millis() < endTime);
                    if (readBytesCount > 0) {
                        if (readBytesCount != STATUS_BUFFER_SIZE) {
                            throw new IOException("Invalid status notification, expected " + STATUS_BUFFER_SIZE + " bytes, got " + readBytesCount);
@ -218,8 +217,9 @@ public class ProlificSerialDriver implements UsbSerialDriver {
                        }
                    }
                }
-            } catch (IOException e) {
-                mReadStatusException = e;
+            } catch (Exception e) {
+                if (isOpen())
+                    mReadStatusException = e;
            }
            //Log.d(TAG, "end control line status thread " + mStopReadStatusThread + " " + (mReadStatusException == null ? "-" : mReadStatusException.getMessage()));
        }
@ -250,8 +250,8 @@ public class ProlificSerialDriver implements UsbSerialDriver {
                }
            }

-            /* throw and clear an exception which occured in the status read thread */
-            IOException readStatusException = mReadStatusException;
+            /* throw and clear an exception which occurred in the status read thread */
+            Exception readStatusException = mReadStatusException;
            if (mReadStatusException != null) {
                mReadStatusException = null;
                throw new IOException(readStatusException);
@ -265,10 +265,10 @@ public class ProlificSerialDriver implements UsbSerialDriver {
        }

        @Override
-        public void openInt(UsbDeviceConnection connection) throws IOException {
+        public void openInt() throws IOException {
            UsbInterface usbInterface = mDevice.getInterface(0);

-            if (!connection.claimInterface(usbInterface, true)) {
+            if (!mConnection.claimInterface(usbInterface, true)) {
                throw new IOException("Error claiming Prolific interface 0");
            }

@ -290,7 +290,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
                }
            }

-            byte[] rawDescriptors = connection.getRawDescriptors();
+            byte[] rawDescriptors = mConnection.getRawDescriptors();
            if(rawDescriptors == null || rawDescriptors.length < 14) {
                throw new IOException("Could not get device descriptors");
            }
@ -299,15 +299,19 @@ public class ProlificSerialDriver implements UsbSerialDriver {
            byte maxPacketSize0 = rawDescriptors[7];
            if (mDevice.getDeviceClass() == 0x02 || maxPacketSize0 != 64) {
                mDeviceType = DeviceType.DEVICE_TYPE_01;
-            } else if(deviceVersion == 0x300 && usbVersion == 0x200) {
-                mDeviceType = DeviceType.DEVICE_TYPE_T; // TA
-            } else if(deviceVersion == 0x500) {
-                mDeviceType = DeviceType.DEVICE_TYPE_T; // TB
-            } else if(usbVersion == 0x200 && !testHxStatus()) {
-                mDeviceType = DeviceType.DEVICE_TYPE_HXN;
+            } else if(usbVersion == 0x200) {
+                if(deviceVersion == 0x300 && testHxStatus()) {
+                    mDeviceType = DeviceType.DEVICE_TYPE_T; // TA
+                } else if(deviceVersion == 0x500 && testHxStatus()) {
+                    mDeviceType = DeviceType.DEVICE_TYPE_T; // TB
+                } else {
+                    mDeviceType = DeviceType.DEVICE_TYPE_HXN;
+                }
            } else {
                mDeviceType = DeviceType.DEVICE_TYPE_HX;
            }
+            Log.d(TAG, String.format("usbVersion=%x, deviceVersion=%x, deviceClass=%d, packetSize=%d => deviceType=%s",
+                    usbVersion, deviceVersion, mDevice.getDeviceClass(), maxPacketSize0, mDeviceType.name()));
            resetDevice();
            doBlackMagic();
            setControlLines(mControlLinesValue);
@ -563,6 +567,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
        }
    }

+    @SuppressWarnings({"unused"})
    public static Map<Integer, int[]> getSupportedDevices() {
        final Map<Integer, int[]> supportedDevices = new LinkedHashMap<>();
        supportedDevices.put(UsbId.VENDOR_PROLIFIC,
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/SerialTimeoutException.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/SerialTimeoutException.java
@ -9,7 +9,8 @@ import java.io.InterruptedIOException;
 * {@see InterruptedIOException#bytesTransferred} may contain bytes transferred
 */
 public class SerialTimeoutException extends InterruptedIOException {
-    public SerialTimeoutException(String s) {
+    public SerialTimeoutException(String s, int bytesTransferred) {
        super(s);
+        this.bytesTransferred = bytesTransferred;
    }
 }
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbId.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbId.java
@ -23,27 +23,6 @@ public final class UsbId {
    public static final int FTDI_FT232H = 0x6014;
    public static final int FTDI_FT231X = 0x6015; // same ID for FT230X, FT231X, FT234XD

-    public static final int VENDOR_ATMEL = 0x03EB;
-    public static final int ATMEL_LUFA_CDC_DEMO_APP = 0x2044;
-
-    public static final int VENDOR_ARDUINO = 0x2341;
-    public static final int ARDUINO_UNO = 0x0001;
-    public static final int ARDUINO_MEGA_2560 = 0x0010;
-    public static final int ARDUINO_SERIAL_ADAPTER = 0x003b;
-    public static final int ARDUINO_MEGA_ADK = 0x003f;
-    public static final int ARDUINO_MEGA_2560_R3 = 0x0042;
-    public static final int ARDUINO_UNO_R3 = 0x0043;
-    public static final int ARDUINO_MEGA_ADK_R3 = 0x0044;
-    public static final int ARDUINO_SERIAL_ADAPTER_R3 = 0x0044;
-    public static final int ARDUINO_LEONARDO = 0x8036;
-    public static final int ARDUINO_MICRO = 0x8037;
-
-    public static final int VENDOR_VAN_OOIJEN_TECH = 0x16c0;
-    public static final int VAN_OOIJEN_TECH_TEENSYDUINO_SERIAL = 0x0483;
-
-    public static final int VENDOR_LEAFLABS = 0x1eaf;
-    public static final int LEAFLABS_MAPLE = 0x0004;
-
    public static final int VENDOR_SILABS = 0x10c4;
    public static final int SILABS_CP2102 = 0xea60; // same ID for CP2101, CP2103, CP2104, CP2109
    public static final int SILABS_CP2105 = 0xea70;
@ -58,16 +37,17 @@ public final class UsbId {
    public static final int PROLIFIC_PL2303GE = 0x23e3; // "
    public static final int PROLIFIC_PL2303GS = 0x23f3; // "

+    public static final int VENDOR_GOOGLE = 0x18d1;
+    public static final int GOOGLE_CR50 = 0x5014;
+
    public static final int VENDOR_QINHENG = 0x1a86;
    public static final int QINHENG_CH340 = 0x7523;
    public static final int QINHENG_CH341A = 0x5523;

-    // at www.linux-usb.org/usb.ids listed for NXP/LPC1768, but all processors supported by ARM mbed DAPLink firmware report these ids
-    public static final int VENDOR_ARM = 0x0d28;
-    public static final int ARM_MBED = 0x0204;
+    public static final int VENDOR_UNISOC = 0x1782;
+    public static final int FIBOCOM_L610 = 0x4D10;
+    public static final int FIBOCOM_L612 = 0x4D12;

-    public static final int VENDOR_ST = 0x0483;
-    public static final int ST_CDC = 0x5740;

    private UsbId() {
        throw new IllegalAccessError("Non-instantiable class");
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialDriver.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialDriver.java
@ -10,12 +10,17 @@ import android.hardware.usb.UsbDevice;

 import java.util.List;

-/**
- *
- * @author mike wakerly (opensource@hoho.com)
- */
 public interface UsbSerialDriver {

+    /*
+     * Additional interface properties. Invoked thru reflection.
+     *
+        UsbSerialDriver(UsbDevice device);                  // constructor with device
+        static Map<Integer, int[]> getSupportedDevices();
+        static boolean probe(UsbDevice device);             // optional
+     */
+
+
    /**
     * Returns the raw {@link UsbDevice} backing this port.
     *
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialPort.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialPort.java
@ -58,7 +58,7 @@ public interface UsbSerialPort extends Closeable {
    int STOPBITS_2 = 2;

    /** Values for get[Supported]ControlLines() */
-    enum ControlLine { RTS, CTS,  DTR, DSR,  CD, RI }
+    enum ControlLine { RTS, CTS, DTR, DSR, CD, RI }

    /**
     * Returns the driver used by this port.
@ -122,6 +122,17 @@ public interface UsbSerialPort extends Closeable {
     */
    int read(final byte[] dest, final int timeout) throws IOException;

+    /**
+     * Reads bytes with specified length into the destination buffer.
+     *
+     * @param dest the destination byte buffer
+     * @param length the maximum length of the data to read
+     * @param timeout the timeout for reading in milliseconds, 0 is infinite
+     * @return the actual number of bytes read
+     * @throws IOException if an error occurred during reading
+     */
+    int read(final byte[] dest, int length, final int timeout) throws IOException;
+
    /**
     * Writes as many bytes as possible from the source buffer.
     *
@ -133,6 +144,18 @@ public interface UsbSerialPort extends Closeable {
     */
    void write(final byte[] src, final int timeout) throws IOException;

+    /**
+     * Writes bytes with specified length from the source buffer.
+     *
+     * @param src the source byte buffer
+     * @param length the length of the data to write
+     * @param timeout the timeout for writing in milliseconds, 0 is infinite
+     * @throws SerialTimeoutException if timeout reached before sending all data.
+     *                                ex.bytesTransferred may contain bytes transferred
+     * @throws IOException if an error occurred during writing
+     */
+    void write(final byte[] src, int length, final int timeout) throws IOException;
+
    /**
     * Sets various serial port parameters.
     *
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialProber.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialProber.java
@ -37,6 +37,8 @@ public class UsbSerialProber {
        probeTable.addDriver(FtdiSerialDriver.class);
        probeTable.addDriver(ProlificSerialDriver.class);
        probeTable.addDriver(Ch34xSerialDriver.class);
+        probeTable.addDriver(GsmModemSerialDriver.class);
+        probeTable.addDriver(ChromeCcdSerialDriver.class);
        return probeTable;
    }

@ -69,11 +71,7 @@ public class UsbSerialProber {
     *         {@code null} if none available.
     */
    public UsbSerialDriver probeDevice(final UsbDevice usbDevice) {
-        final int vendorId = usbDevice.getVendorId();
-        final int productId = usbDevice.getProductId();
-
-        final Class<? extends UsbSerialDriver> driverClass =
-                mProbeTable.findDriver(vendorId, productId);
+        final Class<? extends UsbSerialDriver> driverClass = mProbeTable.findDriver(usbDevice);
        if (driverClass != null) {
            final UsbSerialDriver driver;
            try {
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/HexDump.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/HexDump.java
@ -19,14 +19,17 @@ package com.hoho.android.usbserial.util;
 import java.security.InvalidParameterException;

 /**
- * Clone of Android's HexDump class, for use in debugging. Cosmetic changes
- * only.
+ * Clone of Android's /core/java/com/android/internal/util/HexDump class, for use in debugging.
+ * Changes: space separated hex strings
 */
 public class HexDump {
    private final static char[] HEX_DIGITS = {
            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
    };

+    private HexDump() {
+    }
+
    public static String dumpHexString(byte[] array) {
        return dumpHexString(array, 0, array.length);
    }
@ -82,10 +85,12 @@ public class HexDump {
    }

    public static String toHexString(byte[] array, int offset, int length) {
-        char[] buf = new char[length * 2];
+        char[] buf = new char[length > 0 ? length * 3 - 1 : 0];

        int bufIndex = 0;
        for (int i = offset; i < offset + length; i++) {
+            if (i > offset)
+                buf[bufIndex++] = ' ';
            byte b = array[i];
            buf[bufIndex++] = HEX_DIGITS[(b >>> 4) & 0x0F];
            buf[bufIndex++] = HEX_DIGITS[b & 0x0F];
@ -139,13 +144,13 @@ public class HexDump {
        throw new InvalidParameterException("Invalid hex char '" + c + "'");
    }

+    /** accepts any separator, e.g. space or newline */
    public static byte[] hexStringToByteArray(String hexString) {
        int length = hexString.length();
-        byte[] buffer = new byte[length / 2];
+        byte[] buffer = new byte[(length + 1) / 3];

-        for (int i = 0; i < length; i += 2) {
-            buffer[i / 2] = (byte) ((toByte(hexString.charAt(i)) << 4) | toByte(hexString
-                    .charAt(i + 1)));
+        for (int i = 0; i < length; i += 3) {
+            buffer[i / 3] = (byte) ((toByte(hexString.charAt(i)) << 4) | toByte(hexString.charAt(i + 1)));
        }

        return buffer;
--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/SerialInputOutputManager.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/SerialInputOutputManager.java
@ -9,6 +9,7 @@ package com.hoho.android.usbserial.util;
 import android.os.Process;
 import android.util.Log;

+import com.hoho.android.usbserial.driver.SerialTimeoutException;
 import com.hoho.android.usbserial.driver.UsbSerialPort;

 import java.io.IOException;
@ -21,8 +22,15 @@ import java.nio.ByteBuffer;
 */
 public class SerialInputOutputManager implements Runnable {

-    private static final String TAG = SerialInputOutputManager.class.getSimpleName();
+    public enum State {
+        STOPPED,
+        RUNNING,
+        STOPPING
+    }
+
    public static boolean DEBUG = false;
+
+    private static final String TAG = SerialInputOutputManager.class.getSimpleName();
    private static final int BUFSIZ = 4096;

    /**
@ -37,12 +45,6 @@ public class SerialInputOutputManager implements Runnable {
    private ByteBuffer mReadBuffer; // default size = getReadEndpoint().getMaxPacketSize()
    private ByteBuffer mWriteBuffer = ByteBuffer.allocate(BUFSIZ);

-    public enum State {
-        STOPPED,
-        RUNNING,
-        STOPPING
-    }
-
    private int mThreadPriority = Process.THREAD_PRIORITY_URGENT_AUDIO;
    private State mState = State.STOPPED; // Synchronized by 'this'
    private Listener mListener; // Synchronized by 'this'
@ -202,7 +204,11 @@ public class SerialInputOutputManager implements Runnable {
                step();
            }
        } catch (Exception e) {
-            Log.w(TAG, "Run ending due to exception: " + e.getMessage(), e);
+            if(mSerialPort.isOpen()) {
+                Log.w(TAG, "Run ending due to exception: " + e.getMessage(), e);
+            } else {
+                Log.i(TAG, "Socket closed");
+            }
            final Listener listener = getListener();
            if (listener != null) {
              listener.onRunError(e);
@ -223,7 +229,9 @@ public class SerialInputOutputManager implements Runnable {
        }
        int len = mSerialPort.read(buffer, mReadTimeout);
        if (len > 0) {
-            if (DEBUG) Log.d(TAG, "Read data len=" + len);
+            if (DEBUG) {
+                Log.d(TAG, "Read data len=" + len);
+            }
            final Listener listener = getListener();
            if (listener != null) {
                final byte[] data = new byte[len];
@ -247,7 +255,23 @@ public class SerialInputOutputManager implements Runnable {
            if (DEBUG) {
                Log.d(TAG, "Writing data len=" + len);
            }
-            mSerialPort.write(buffer, mWriteTimeout);
+            try {
+                mSerialPort.write(buffer, mWriteTimeout);
+            } catch (SerialTimeoutException ex) {
+                synchronized (mWriteBufferLock) {
+                    byte[] buffer2 = null;
+                    int len2 = mWriteBuffer.position();
+                    if (len2 > 0) {
+                        buffer2 = new byte[len2];
+                        mWriteBuffer.rewind();
+                        mWriteBuffer.get(buffer2, 0, len2);
+                        mWriteBuffer.clear();
+                    }
+                    mWriteBuffer.put(buffer, ex.bytesTransferred, buffer.length - ex.bytesTransferred);
+                    if (buffer2 != null)
+                        mWriteBuffer.put(buffer2);
+                }
+            }
        }
    }

--- a/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/UsbUtils.java
+++ b/usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/UsbUtils.java
@ -0,0 +1,33 @@
+package com.hoho.android.usbserial.util;
+
+import android.hardware.usb.UsbDeviceConnection;
+
+import java.util.ArrayList;
+
+public class UsbUtils {
+
+    private UsbUtils() {
+    }
+
+    public static  ArrayList<byte[]> getDescriptors(UsbDeviceConnection connection) {
+        ArrayList<byte[]> descriptors = new ArrayList<>();
+        byte[] rawDescriptors = connection.getRawDescriptors();
+        if (rawDescriptors != null) {
+            int pos = 0;
+            while (pos < rawDescriptors.length) {
+                int len = rawDescriptors[pos] & 0xFF;
+                if (len == 0)
+                    break;
+                if (pos + len > rawDescriptors.length)
+                    len = rawDescriptors.length - pos;
+                byte[] descriptor = new byte[len];
+                System.arraycopy(rawDescriptors, pos, descriptor, 0, len);
+                descriptors.add(descriptor);
+                pos += len;
+            }
+        }
+        return descriptors;
+    }
+
+
+}
--- a/usbSerialForAndroid/src/test/java/android/util/Log.java
+++ b/usbSerialForAndroid/src/test/java/android/util/Log.java
@ -0,0 +1,24 @@
+// without this class Mockito complains about non-mocked Log methods
+package android.util;
+
+public class Log {
+    public static int d(String tag, String msg) {
+        System.out.println("DEBUG: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int i(String tag, String msg) {
+        System.out.println("INFO: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int w(String tag, String msg) {
+        System.out.println("WARN: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int e(String tag, String msg) {
+        System.out.println("ERROR: " + tag + ": " + msg);
+        return 0;
+    }
+}
--- a/usbSerialForAndroid/src/test/java/android/util/Pair.java
+++ b/usbSerialForAndroid/src/test/java/android/util/Pair.java
@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+
+import androidx.annotation.Nullable;
+
+import java.util.Objects;
+
+/**
+ * Container to ease passing around a tuple of two objects. This object provides a sensible
+ * implementation of equals(), returning true if equals() is true on each of the contained
+ * objects.
+ */
+public class Pair<F, S> {
+    public final F first;
+    public final S second;
+
+    /**
+     * Constructor for a Pair.
+     *
+     * @param first the first object in the Pair
+     * @param second the second object in the pair
+     */
+    public Pair(F first, S second) {
+        this.first = first;
+        this.second = second;
+    }
+
+    /**
+     * Checks the two objects for equality by delegating to their respective
+     * {@link Object#equals(Object)} methods.
+     *
+     * @param o the {@link Pair} to which this one is to be checked for equality
+     * @return true if the underlying objects of the Pair are both considered
+     *         equal
+     */
+    @Override
+    public boolean equals(@Nullable Object o) {
+        if (!(o instanceof Pair)) {
+            return false;
+        }
+        Pair<?, ?> p = (Pair<?, ?>) o;
+        return Objects.equals(p.first, first) && Objects.equals(p.second, second);
+    }
+
+    /**
+     * Compute a hash code using the hash codes of the underlying objects
+     *
+     * @return a hashcode of the Pair
+     */
+    @Override
+    public int hashCode() {
+        return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
+    }
+
+    @Override
+    public String toString() {
+        return "Pair{" + String.valueOf(first) + " " + String.valueOf(second) + "}";
+    }
+
+    /**
+     * Convenience method for creating an appropriately typed pair.
+     * @param a the first object in the Pair
+     * @param b the second object in the pair
+     * @return a Pair that is templatized with the types of a and b
+     */
+    public static <A, B> Pair <A, B> create(A a, B b) {
+        return new Pair<A, B>(a, b);
+    }
+}
--- a/usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriverTest.java
+++ b/usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriverTest.java
@ -0,0 +1,546 @@
+package com.hoho.android.usbserial.driver;
+
+import static com.hoho.android.usbserial.driver.CdcAcmSerialDriver.USB_SUBCLASS_ACM;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.clearInvocations;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.hardware.usb.UsbConstants;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbDeviceConnection;
+import android.hardware.usb.UsbEndpoint;
+import android.hardware.usb.UsbInterface;
+
+import com.hoho.android.usbserial.util.HexDump;
+
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class CdcAcmSerialDriverTest {
+
+    @Test
+    public void standardDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        /*
+         * digispark - no IAD
+         *   UsbInterface[mId=0,mAlternateSetting=0,mName=null,mClass=2,mSubclass=2,mProtocol=1,mEndpoints=[
+         *     UsbEndpoint[mAddress=131,mAttributes=3,mMaxPacketSize=8,mInterval=255]]
+         *   UsbInterface[mId=1,mAlternateSetting=0,mName=null,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=1,mAttributes=2,mMaxPacketSize=8,mInterval=0]
+         *     UsbEndpoint[mAddress=129,mAttributes=2,mMaxPacketSize=8,mInterval=0]]
+         */
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 10 01 02 00 00 08 D0 16 7E 08 00 01 01 02 00 01\n" +
+                "09 02 43 00 02 01 00 80 32\n" +
+                "09 04 00 00 01 02 02 01 00\n" +
+                "05 24 00 10 01\n" +
+                "04 24 02 02\n" +
+                "05 24 06 00 01\n" +
+                "05 24 01 03 01\n" +
+                "07 05 83 03 08 00 FF\n" +
+                "09 04 01 00 02 0A 00 00 00\n" +
+                "07 05 01 02 08 00 00\n" +
+                "07 05 81 02 08 00 00"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(2);
+        when(usbDevice.getInterface(0)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(dataInterface);
+        when(controlInterface.getId()).thenReturn(0);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getId()).thenReturn(1);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+
+        ProbeTable probeTable = UsbSerialProber.getDefaultProbeTable();
+        Class<? extends UsbSerialDriver> probeDriver = probeTable.findDriver(usbDevice);
+        assertEquals(driver.getClass(), probeDriver);
+    }
+
+    @Test
+    public void singleInterfaceDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface usbInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        when(usbDeviceConnection.claimInterface(usbInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(1);
+        when(usbDevice.getInterface(0)).thenReturn(usbInterface);
+        when(usbInterface.getEndpointCount()).thenReturn(3);
+        when(usbInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(usbInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(usbInterface.getEndpoint(2)).thenReturn(writeEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+
+        ProbeTable probeTable = UsbSerialProber.getDefaultProbeTable();
+        Class<? extends UsbSerialDriver> probeDriver = probeTable.findDriver(usbDevice);
+        assertNull(probeDriver);
+    }
+
+    @Test
+    public void multiPortDevice() throws Exception {
+        int n = 2;
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface[] controlInterfaces = new UsbInterface[n];
+        UsbInterface[] dataInterfaces = new UsbInterface[n];
+        UsbEndpoint[] controlEndpoints = new UsbEndpoint[n];
+        UsbEndpoint[] readEndpoints = new UsbEndpoint[n];
+        UsbEndpoint[] writeEndpoints = new UsbEndpoint[n];
+
+        /*
+         * pi zero - dual port
+         *   UsbInterface[mId=0,mAlternateSetting=0,mName=TinyUSB CDC,mClass=2,mSubclass=2,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=129,mAttributes=3,mMaxPacketSize=8,mInterval=16]]
+         *   UsbInterface[mId=1,mAlternateSetting=0,mName=null,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=2,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *     UsbEndpoint[mAddress=130,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         *   UsbInterface[mId=2,mAlternateSetting=0,mName=TinyUSB CDC,mClass=2,mSubclass=2,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=131,mAttributes=3,mMaxPacketSize=8,mInterval=16]]
+         *   UsbInterface[mId=3,mAlternateSetting=0,mName=null,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=4,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *      UsbEndpoint[mAddress=132,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         */
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 00 02 EF 02 01 40 FE CA 02 40 00 01 01 02 03 01\n" +
+                "09 02 8D 00 04 01 00 80 32\n" +
+                "08 0B 00 02 02 02 00 00\n" +
+                "09 04 00 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 01\n" +
+                "04 24 02 02\n" +
+                "05 24 06 00 01\n" +
+                "07 05 81 03 08 00 10\n" +
+                "09 04 01 00 02 0A 00 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "07 05 82 02 40 00 00\n" +
+                "08 0B 02 02 02 02 00 00\n" +
+                "09 04 02 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 03\n" +
+                "04 24 02 02\n" +
+                "05 24 06 02 03\n" +
+                "07 05 83 03 08 00 10\n" +
+                "09 04 03 00 02 0A 00 00 00\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00\n"));
+        when(usbDevice.getInterfaceCount()).thenReturn(2*n);
+        for(int i=0; i<n; i++) {
+            controlInterfaces[i] = mock(UsbInterface.class);
+            dataInterfaces[i] = mock(UsbInterface.class);
+            controlEndpoints[i] = mock(UsbEndpoint.class);
+            readEndpoints[i] = mock(UsbEndpoint.class);
+            writeEndpoints[i] = mock(UsbEndpoint.class);
+            when(usbDeviceConnection.claimInterface(controlInterfaces[i], true)).thenReturn(true);
+            when(usbDeviceConnection.claimInterface(dataInterfaces[i], true)).thenReturn(true);
+            when(usbDevice.getInterface(2*i  )).thenReturn(controlInterfaces[i]);
+            when(usbDevice.getInterface(2*i+1)).thenReturn(dataInterfaces[i]);
+            when(controlInterfaces[i].getId()).thenReturn(2*i);
+            when(controlInterfaces[i].getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+            when(controlInterfaces[i].getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+            when(controlInterfaces[i].getEndpointCount()).thenReturn(1);
+            when(controlInterfaces[i].getEndpoint(0)).thenReturn(controlEndpoints[i]);
+            when(dataInterfaces[i].getId()).thenReturn(2*i+1);
+            when(dataInterfaces[i].getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+            when(dataInterfaces[i].getEndpointCount()).thenReturn(2);
+            when(dataInterfaces[i].getEndpoint(0)).thenReturn(writeEndpoints[i]);
+            when(dataInterfaces[i].getEndpoint(1)).thenReturn(readEndpoints[i]);
+            when(controlEndpoints[i].getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+            when(controlEndpoints[i].getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+            when(readEndpoints[i].getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+            when(readEndpoints[i].getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+            when(writeEndpoints[i].getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+            when(writeEndpoints[i].getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        }
+        int i = 1;
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(i);
+        port.mConnection = usbDeviceConnection;
+        // reset invocations from countPorts()
+        clearInvocations(controlInterfaces[0]);
+        clearInvocations(controlInterfaces[1]);
+
+        port.openInt();
+        assertEquals(readEndpoints[i], port.mReadEndpoint);
+        assertEquals(writeEndpoints[i], port.mWriteEndpoint);
+        verify(controlInterfaces[0], times(0)).getInterfaceClass(); // not openInterface with 'no IAD fallback'
+        verify(controlInterfaces[1], times(2)).getInterfaceClass(); // openInterface with IAD
+        port.closeInt();
+        clearInvocations(controlInterfaces[0]);
+        clearInvocations(controlInterfaces[1]);
+
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(null);
+        port.openInt();
+        verify(controlInterfaces[0], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+        verify(controlInterfaces[1], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+        port.closeInt();
+        clearInvocations(controlInterfaces[0]);
+        clearInvocations(controlInterfaces[1]);
+
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray("01 02 02 82 02")); // truncated descriptor
+        port.openInt();
+        verify(controlInterfaces[0], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+        verify(controlInterfaces[1], times(2)).getInterfaceClass(); // openInterface with 'no IAD fallback'
+    }
+
+    @Test
+    public void compositeDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface massStorageInterface = mock(UsbInterface.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbInterface hidInterface = mock(UsbInterface.class);
+        UsbInterface vendorInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        /*
+         * BBC micro:bit
+         *   UsbInterface[mId=0,mAlternateSetting=0,mName=USB_MSC,mClass=8,mSubclass=6,mProtocol=80,mEndpoints=[
+         *     UsbEndpoint[mAddress=130,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *     UsbEndpoint[mAddress=2,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         *   UsbInterface[mId=1,mAlternateSetting=0,mName=mbed Serial Port,mClass=2,mSubclass=2,mProtocol=1,mEndpoints=[
+         *     UsbEndpoint[mAddress=131,mAttributes=3,mMaxPacketSize=16,mInterval=32]]
+         *   UsbInterface[mId=2,mAlternateSetting=0,mName=mbed Serial Port,mClass=10,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=4,mAttributes=2,mMaxPacketSize=64,mInterval=0]
+         *     UsbEndpoint[mAddress=132,mAttributes=2,mMaxPacketSize=64,mInterval=0]]
+         *   UsbInterface[mId=3,mAlternateSetting=0,mName=CMSIS-DAP,mClass=3,mSubclass=0,mProtocol=0,mEndpoints=[
+         *     UsbEndpoint[mAddress=129,mAttributes=3,mMaxPacketSize=64,mInterval=1]
+         *     UsbEndpoint[mAddress=1,mAttributes=3,mMaxPacketSize=64,mInterval=1]]
+         *   UsbInterface[mId=4,mAlternateSetting=0,mName=WebUSB: CMSIS-DAP,mClass=255,mSubclass=3,mProtocol=0,mEndpoints=[]
+         */
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 10 02 EF 02 01 40 28 0D 04 02 00 10 01 02 03 01\n" +
+                "09 02 8B 00 05 01 00 80 FA\n" +
+                "09 04 00 00 02 08 06 50 08\n" +
+                "07 05 82 02 40 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "08 0B 01 02 02 02 01 04\n" +
+                "09 04 01 00 01 02 02 01 04\n" +
+                "05 24 00 10 01\n" +
+                "05 24 01 03 02\n" +
+                "04 24 02 06\n" +
+                "05 24 06 01 02\n" +
+                "07 05 83 03 10 00 20\n" +
+                "09 04 02 00 02 0A 00 00 05\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00\n" +
+                "09 04 03 00 02 03 00 00 06\n" +
+                "09 21 00 01 00 01 22 21 00\n" +
+                "07 05 81 03 40 00 01\n" +
+                "07 05 01 03 40 00 01\n" +
+                "09 04 04 00 00 FF 03 00 07"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(5);
+        when(usbDevice.getInterface(0)).thenReturn(massStorageInterface);
+        when(usbDevice.getInterface(1)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(2)).thenReturn(dataInterface);
+        when(usbDevice.getInterface(3)).thenReturn(hidInterface);
+        when(usbDevice.getInterface(4)).thenReturn(vendorInterface);
+        when(massStorageInterface.getId()).thenReturn(0);
+        when(massStorageInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_MASS_STORAGE);
+        when(controlInterface.getId()).thenReturn(1);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(dataInterface.getId()).thenReturn(2);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(hidInterface.getId()).thenReturn(3);
+        when(hidInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_HID);
+        when(vendorInterface.getId()).thenReturn(4);
+        when(vendorInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_VENDOR_SPEC);
+
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+
+        ProbeTable probeTable = UsbSerialProber.getDefaultProbeTable();
+        Class<? extends UsbSerialDriver> probeDriver = probeTable.findDriver(usbDevice);
+        assertEquals(driver.getClass(), probeDriver);
+    }
+
+    @Test
+    public void compositeRndisDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface rndisControlInterface = mock(UsbInterface.class);
+        UsbInterface rndisDataInterface = mock(UsbInterface.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        // has multiple USB_CLASS_CDC_DATA interfaces => get correct with IAD
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 00 02 EF 02 01 40 FE CA 02 40 00 01 01 02 03 01\n" +
+                "09 02 8D 00 04 01 00 80 32\n" +
+                "08 0B 00 02 E0 01 03 00\n" +
+                "09 04 00 00 01 E0 01 03 04\n" +
+                "05 24 00 10 01\n" +
+                "05 24 01 00 01\n" +
+                "04 24 02 00\n" +
+                "05 24 06 00 01\n" +
+                "07 05 81 03 08 00 01\n" +
+                "09 04 01 00 02 0A 00 00 00\n" +
+                "07 05 82 02 40 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "08 0B 02 02 02 02 00 00\n" +
+                "09 04 02 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 03\n" +
+                "04 24 02 02\n" +
+                "05 24 06 02 03\n" +
+                "07 05 83 03 08 00 10\n" +
+                "09 04 03 00 02 0A 00 00 00\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(4);
+        when(usbDevice.getInterface(0)).thenReturn(rndisControlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(rndisDataInterface);
+        when(usbDevice.getInterface(2)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(3)).thenReturn(dataInterface);
+        when(rndisControlInterface.getId()).thenReturn(0);
+        when(rndisControlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_WIRELESS_CONTROLLER);
+        when(rndisControlInterface.getInterfaceSubclass()).thenReturn(1);
+        when(rndisControlInterface.getInterfaceProtocol()).thenReturn(3);
+        when(rndisDataInterface.getId()).thenReturn(1);
+        when(rndisDataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(controlInterface.getId()).thenReturn(2);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(dataInterface.getId()).thenReturn(3);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+    }
+
+    @Test
+    public void compositeAlternateSettingDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface ethernetControlInterface = mock(UsbInterface.class);
+        UsbInterface ethernetDummyInterface = mock(UsbInterface.class);
+        UsbInterface ethernetDataInterface = mock(UsbInterface.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        // has multiple USB_CLASS_CDC_DATA interfaces => get correct with IAD
+        when(usbDeviceConnection.getRawDescriptors()).thenReturn(HexDump.hexStringToByteArray(
+                "12 01 00 02 EF 02 01 40 FE CA 02 40 00 01 01 02 03 01\n" +
+                "09 02 9A 00 04 01 00 80 32\n" +
+                "08 0B 00 02 02 06 00 00\n" +
+                "09 04 00 00 01 02 06 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 06 00 01\n" +
+                "0D 24 0F 04 00 00 00 00 DC 05 00 00 00\n" +
+                "07 05 81 03 08 00 01\n" +
+                "09 04 01 00 00 0A 00 00 00\n" +
+                "09 04 01 01 02 0A 00 00 00\n" +
+                "07 05 82 02 40 00 00\n" +
+                "07 05 02 02 40 00 00\n" +
+                "08 0B 02 02 02 02 00 00\n" +
+                "09 04 02 00 01 02 02 00 04\n" +
+                "05 24 00 20 01\n" +
+                "05 24 01 00 03\n" +
+                "04 24 02 02\n" +
+                "05 24 06 02 03\n" +
+                "07 05 83 03 08 00 10\n" +
+                "09 04 03 00 02 0A 00 00 00\n" +
+                "07 05 04 02 40 00 00\n" +
+                "07 05 84 02 40 00 00"));
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(5);
+        when(usbDevice.getInterface(0)).thenReturn(ethernetControlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(ethernetDummyInterface);
+        when(usbDevice.getInterface(2)).thenReturn(ethernetDataInterface);
+        when(usbDevice.getInterface(3)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(4)).thenReturn(dataInterface);
+        when(ethernetControlInterface.getId()).thenReturn(0);
+        when(ethernetControlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(ethernetControlInterface.getInterfaceSubclass()).thenReturn(6);
+        when(ethernetDummyInterface.getId()).thenReturn(1);
+        when(ethernetDummyInterface.getAlternateSetting()).thenReturn(0);
+        when(ethernetDummyInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(ethernetDataInterface.getId()).thenReturn(1);
+        when(ethernetDataInterface.getAlternateSetting()).thenReturn(1);
+        when(ethernetDataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(controlInterface.getId()).thenReturn(2);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(dataInterface.getId()).thenReturn(3);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertEquals(readEndpoint, port.mReadEndpoint);
+        assertEquals(writeEndpoint, port.mWriteEndpoint);
+    }
+
+    @Test
+    public void invalidStandardDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface controlInterface = mock(UsbInterface.class);
+        UsbInterface dataInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        when(usbDeviceConnection.claimInterface(controlInterface,true)).thenReturn(true);
+        when(usbDeviceConnection.claimInterface(dataInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(2);
+        when(usbDevice.getInterface(0)).thenReturn(controlInterface);
+        when(usbDevice.getInterface(1)).thenReturn(dataInterface);
+        when(controlInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_COMM);
+        when(controlInterface.getInterfaceSubclass()).thenReturn(USB_SUBCLASS_ACM);
+        when(controlInterface.getEndpointCount()).thenReturn(1);
+        when(controlInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(dataInterface.getInterfaceClass()).thenReturn(UsbConstants.USB_CLASS_CDC_DATA);
+        when(dataInterface.getEndpointCount()).thenReturn(2);
+        when(dataInterface.getEndpoint(0)).thenReturn(writeEndpoint);
+        when(dataInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        //when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        //when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        assertThrows(IOException.class, port::openInt);
+    }
+
+    @Test
+    public void invalidSingleInterfaceDevice() throws Exception {
+        UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
+        UsbDevice usbDevice = mock(UsbDevice.class);
+        UsbInterface usbInterface = mock(UsbInterface.class);
+        UsbEndpoint controlEndpoint = mock(UsbEndpoint.class);
+        UsbEndpoint readEndpoint = mock(UsbEndpoint.class);
+        //UsbEndpoint writeEndpoint = mock(UsbEndpoint.class);
+
+        when(usbDeviceConnection.claimInterface(usbInterface,true)).thenReturn(true);
+        when(usbDevice.getInterfaceCount()).thenReturn(1);
+        when(usbDevice.getInterface(0)).thenReturn(usbInterface);
+        when(usbInterface.getEndpointCount()).thenReturn(2);
+        when(usbInterface.getEndpoint(0)).thenReturn(controlEndpoint);
+        when(usbInterface.getEndpoint(1)).thenReturn(readEndpoint);
+        //when(usbInterface.getEndpoint(2)).thenReturn(writeEndpoint);
+        when(controlEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(controlEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_INT);
+        when(readEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_IN);
+        when(readEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+        //when(writeEndpoint.getDirection()).thenReturn(UsbConstants.USB_DIR_OUT);
+        //when(writeEndpoint.getType()).thenReturn(UsbConstants.USB_ENDPOINT_XFER_BULK);
+
+        CdcAcmSerialDriver driver = new CdcAcmSerialDriver(usbDevice);
+        CdcAcmSerialDriver.CdcAcmSerialPort port = (CdcAcmSerialDriver.CdcAcmSerialPort) driver.getPorts().get(0);
+        port.mConnection = usbDeviceConnection;
+        port.openInt();
+        assertNull(port.mWriteEndpoint);
+    }
+
+}
--- a/usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/util/HexDumpText.java
+++ b/usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/util/HexDumpText.java
@ -0,0 +1,44 @@
+package com.hoho.android.usbserial.util;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+
+import org.junit.Test;
+
+import java.security.InvalidParameterException;
+
+public class HexDumpText {
+
+    @Test
+    public void toByteArray() throws Exception {
+        assertThat(HexDump.toByteArray((byte)0x4a), equalTo(new byte[]{ 0x4A}));
+        assertThat(HexDump.toByteArray((short)0x4a5b), equalTo(new byte[]{ 0x4A, 0x5B}));
+        assertThat(HexDump.toByteArray((int)0x4a5b6c7d), equalTo(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}));
+    }
+
+    @Test
+    public void toHexString() throws Exception {
+        assertEquals("4A", HexDump.toHexString((byte)0x4a));
+        assertEquals("4A 5B", HexDump.toHexString((short)0x4a5b));
+        assertEquals("4A 5B 6C 7D", HexDump.toHexString((int)0x4a5b6c7d));
+        assertEquals("4A 5B 6C 7D", HexDump.toHexString(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}));
+        assertEquals("5B 6C", HexDump.toHexString(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}, 1, 2));
+    }
+
+    @Test
+    public void dumpHexString() throws Exception {
+        assertEquals("10 31 32 33 34 35 36 37 .1234567\n18 39                   .9", HexDump.dumpHexString(new byte[]{ 0x10, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x18, 0x39}));
+        assertEquals("31 32                   12", HexDump.dumpHexString(new byte[]{ 0x30, 0x31, 0x32, 0x33}, 1, 2));
+    }
+
+    @Test
+    public void toByte() throws Exception {
+        assertThat(HexDump.hexStringToByteArray("4a 5B-6c\n7d"), equalTo(new byte[]{ 0x4A, 0x5B, 0x6C, 0x7D}));
+        assertThrows(InvalidParameterException.class, () -> HexDump.hexStringToByteArray("3 "));
+        assertThrows(InvalidParameterException.class, () -> HexDump.hexStringToByteArray("3z"));
+        assertThrows(InvalidParameterException.class, () -> HexDump.hexStringToByteArray("3Z"));
+    }
+
+}
Autor	SHA1	Wiadomość	Data
kai-morich	275590027b	Update README.md	2024-06-02 15:09:07 +02:00
Kai Morich	b6e1833270	test coverage	2024-06-02 14:52:39 +02:00
Kai Morich	b794092c81	improved error handling for read() with concurrent close() (#569 ) reworked previous solution from change `8b9ad7ef` / v3.7.1 because closeInt() was not working any more	2024-06-02 10:16:56 +02:00
Kai Morich	b1362416f0	gradle + library update	2024-06-01 14:46:38 +02:00
Kai Morich	0c0275675f	SerialInputOutputManager.writeAsync(): handle SerialTimeoutException	2024-06-01 14:46:38 +02:00
Kai Morich	cab862599d	write(): throw SerialTimeoutException if connection still valid	2024-06-01 14:46:38 +02:00
Holden	2fbceb6cc7	Fix ControlLine enum spacing (#577 )	2024-06-01 10:07:38 +02:00
kai-morich	a4ee5c2158	Update README.md	2024-05-13 22:19:37 +02:00
Kai Morich	9bc3834eff	handle uncaught NPE causing App termination in prolific driver controlline background thread	2024-05-13 22:07:27 +02:00
Kai Morich	28506a9bf9	assert warning cleanup	2024-05-03 08:47:22 +02:00
Kai Morich	8b9ad7efdf	improved error handling for read() with concurrent close() (#569 ) - isOpen() returns false during concurrent close() - less tracing in SerialInputOutputManager	2024-04-25 18:24:28 +02:00
Kai Morich	1245293888	harmonize controlTransfer() result comparison	2024-02-18 13:34:08 +01:00
Kai Morich	26a2f9363e	target sdk 34 Pending intent and broadcast receiver changed according to sdk 34 release notes. Permisssion dialog now shown while fragment is paused.	2024-02-18 13:30:50 +01:00
Kai Morich	83646d6955	gradle 8.2	2024-02-18 12:19:46 +01:00
Self Not Found	573c7e41ca	Add read() and write() with length argument (#544 ) To reduce array copy	2023-11-08 21:12:30 +01:00
kai-morich	880c0070cb	3.7.0 in README	2023-10-15 17:07:10 +02:00
kai-morich	a1709c3911	mention gradle kotlin DSL (#537 )	2023-10-15 17:06:14 +02:00
kai-morich	9c30dc5ffa	update build workflow versions	2023-10-02 19:12:33 +02:00
kai-morich	b06118b156	consolidate get[Supported]ControlLines	2023-10-02 19:05:55 +02:00
kai-morich	de6d5aa384	replace tab with spaces	2023-10-02 15:52:25 +02:00
kai-morich	11ccb5b949	add missing ChromeCcd setParameters	2023-10-02 08:36:50 +02:00
kai-morich	d585ca8be7	add ChromeCcd to readme	2023-10-02 08:29:22 +02:00
Vladimir Serbinenko	2a2463cd12	Add support for Cr50 (Chromebook CCD) (#540 )	2023-10-02 08:19:57 +02:00
kai-morich	80a555a189	v3.6.0 in readme	2023-09-06 07:54:30 +02:00
kai-morich	34e6d989fd	fix codacy badge in README.md	2023-08-25 08:51:25 +02:00
kai-morich	35fdeb1e13	improved exception type also for read with timeout	2023-08-24 19:51:47 +02:00
ExPl0siF	399d3c9c2f	Added error management inside read function to get more appropriate exception (#529 )	2023-08-24 18:49:29 +02:00
kai-morich	54ff9bfa44	composite CDC devices: get correct ACM data interface from IAD (#499 )	2023-08-23 07:55:31 +02:00
kai-morich	7aecce7943	util/HexDump with space separated hex strings	2023-07-31 08:23:35 +02:00
kai-morich	d15f4d52bb	move util/HexDump class from example to library	2023-07-31 08:23:35 +02:00
kai-morich	fd8c155ca5	Merge pull request #521 from elicec/master add gsm modem usb driver	2023-07-31 08:19:24 +02:00
elicec	88b74d716c	add GSM Modem usb device driver	2023-07-31 08:57:34 +08:00
kai-morich	e9a38ca891	skip non ACM subclasses for CDC composite devices	2023-07-24 19:12:18 +02:00
kai-morich	a9c835bcb0	gradle 8.0	2023-07-04 20:52:08 +02:00
kai-morich	9bd1f25773	version update in README	2023-03-15 07:47:48 +01:00
kai-morich	083b9ae7fe	use correct control index for composite CDC devices with non-consecutive interface IDs (#477 )	2023-03-15 07:47:27 +01:00
kai-morich	fd551970be	no code changes, just use normal line breaks	2023-03-15 07:47:08 +01:00
kai-morich	5db45548ba	probe CDC devices by USB interface types instead of fixed VID+PID - no more custom prober required for standard CDC devices - legacy (singleInterface) CDC devices still have to be added by VID+PID - for autostart VID+PID still have to be added to device_filter.xml	2023-03-11 19:12:42 +01:00
kai-morich	85f64aff96	skip RNDIS related data interfaces in composite CDC devices (#469 )	2023-03-11 17:42:13 +01:00
kai-morich	6c648e9f56	have to use MUTABLE to get GRANTED flag at intent extras	2023-03-11 17:42:12 +01:00
kai-morich	dd1b95b852	target sdk 33	2023-03-11 17:42:12 +01:00
kai-morich	7ea76f8899	cdcacm unit test	2023-03-11 17:42:12 +01:00
kai-morich	fbe64fe4be	gradle update, coverage working again	2023-03-11 17:42:12 +01:00
kai-morich	8d3326ed66	remove redundant parameter	2023-03-11 17:42:12 +01:00
kai-morich	6ffb666b33	Merge pull request #464 from chobitsfan/patch-2 update adding repository	2023-01-12 17:25:01 +01:00
kai-morich	e3085eacce	clarified condition for alternative repo setting	2023-01-12 17:21:32 +01:00
Chobits Tai	589b8a0fbf	update adding repository	2023-01-04 14:10:54 +08:00
kai-morich	5bb8db02d5	Update README.md mention Qinheng CH9102	2022-07-22 08:12:37 +02:00
kai-morich	963ae1d243	version update	2022-07-22 08:03:51 +02:00
kai-morich	ab27c19dc3	sdk 31 fixes: pending intent mutability	2022-07-21 21:59:36 +02:00
kai-morich	1091b4d88b	improve PL2303 device type detection (#439 )	2022-07-21 12:56:59 +02:00
kai-morich	b0e956c5b3	Merge pull request #440 from majbthrd/addCH9102F added VID/PID for Qinheng CH9102F	2022-07-21 07:58:56 +02:00
Peter Lawrence	82aeccbf1c	added VID/PID for Qinheng CH9102F	2022-07-20 17:21:00 -05:00
kai-morich	f8e76c9b3b	updated version in dependency example	2022-07-17 16:05:02 +02:00
kai-morich	1d4e0128c0	added VID/PID for Raspberry Pi Pico SDK	2022-07-05 07:29:25 +02:00
kai-morich	f997a8b68a	log prolific device type	2022-05-18 08:27:27 +02:00
kai-morich	cf9bada887	use optimal write buffer size by default + revert gradle update write buffer: SerialTimeoutException from write() has valid ex.bytesTransferred gradle 7.1.x creates empty coverage results	2022-04-26 21:40:49 +02:00
kai-morich	b853ac773c	test concurrent access on multi-port devices	2022-04-19 22:17:23 +02:00
kai-morich	1f35587739	target-sdk + dependency update	2022-04-19 20:55:34 +02:00
kai-morich	dea836d8ce	Merge pull request #411 from Glass-Imaging/rp2_support Add support for Raspberry Pi Pico	2022-02-13 13:09:45 +01:00
Doug MacEwen	a2fa5f010a	Specify Support is only for Micropython	2022-02-11 11:32:51 -08:00
Doug MacEwen	49ee2d3c8e	Add support for Raspberry Pi Pico	2022-02-08 16:08:49 -08:00
kai-morich	896b242be0	switch openjdk distribution for build action	2021-10-06 08:29:15 +02:00
kai-morich	bdfb7d5f6c	reordered public members	2021-09-26 08:09:39 +02:00
kai-morich	76f9198c02	more configurable debug log, disabled by default (#389 )	2021-09-26 08:02:20 +02:00