diff --git a/libraries/Adafruit_BusIO/.github/workflows/githubci.yml b/libraries/Adafruit_BusIO/.github/workflows/githubci.yml
index bfce51b..568eda2 100755
--- a/libraries/Adafruit_BusIO/.github/workflows/githubci.yml
+++ b/libraries/Adafruit_BusIO/.github/workflows/githubci.yml
@@ -16,17 +16,17 @@ jobs:
          repository: adafruit/ci-arduino
          path: ci
 
-    - name: pre-install
+    - name: Install the prerequisites
       run: bash ci/actions_install.sh
 
-    - name: test platforms
-      run: python3 ci/build_platform.py main_platforms
+    - name: Check for correct code formatting with clang-format
+      run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -r .
 
-    - name: clang
-      run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -r . 
-
-    - name: doxygen
+    - name: Check for correct documentation with doxygen
       env:
         GH_REPO_TOKEN: ${{ secrets.GH_REPO_TOKEN }}
         PRETTYNAME : "Adafruit Bus IO Library"
       run: bash ci/doxy_gen_and_deploy.sh
+
+    - name: Test the code on supported platforms
+      run: python3 ci/build_platform.py main_platforms zero feather32u4
diff --git a/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.cpp b/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.cpp
index f802525..a28193f 100755
--- a/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.cpp
+++ b/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.cpp
@@ -21,7 +21,7 @@ Adafruit_BusIO_Register::Adafruit_BusIO_Register(Adafruit_I2CDevice *i2cdevice,
                                                  uint8_t byteorder,
                                                  uint8_t address_width) {
   _i2cdevice = i2cdevice;
-  _spidevice = NULL;
+  _spidevice = nullptr;
   _addrwidth = address_width;
   _address = reg_addr;
   _byteorder = byteorder;
@@ -50,7 +50,7 @@ Adafruit_BusIO_Register::Adafruit_BusIO_Register(Adafruit_SPIDevice *spidevice,
                                                  uint8_t address_width) {
   _spidevice = spidevice;
   _spiregtype = type;
-  _i2cdevice = NULL;
+  _i2cdevice = nullptr;
   _addrwidth = address_width;
   _address = reg_addr;
   _byteorder = byteorder;
@@ -59,12 +59,12 @@ Adafruit_BusIO_Register::Adafruit_BusIO_Register(Adafruit_SPIDevice *spidevice,
 
 /*!
  *    @brief  Create a register we access over an I2C or SPI Device. This is a
- * handy function because we can pass in NULL for the unused interface, allowing
- * libraries to mass-define all the registers
- *    @param  i2cdevice The I2CDevice to use for underlying I2C access, if NULL
- * we use SPI
- *    @param  spidevice The SPIDevice to use for underlying SPI access, if NULL
- * we use I2C
+ * handy function because we can pass in nullptr for the unused interface,
+ * allowing libraries to mass-define all the registers
+ *    @param  i2cdevice The I2CDevice to use for underlying I2C access, if
+ * nullptr we use SPI
+ *    @param  spidevice The SPIDevice to use for underlying SPI access, if
+ * nullptr we use I2C
  *    @param  reg_addr The address pointer value for the I2C/SMBus/SPI register,
  * can be 8 or 16 bits
  *    @param  type     The method we use to read/write data to SPI (which is not
diff --git a/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.h b/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.h
index 8454b21..c6d58de 100755
--- a/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.h
+++ b/libraries/Adafruit_BusIO/Adafruit_BusIO_Register.h
@@ -1,12 +1,13 @@
-#include <Adafruit_I2CDevice.h>
-#include <Adafruit_SPIDevice.h>
+#ifndef Adafruit_BusIO_Register_h
+#define Adafruit_BusIO_Register_h
+
 #include <Arduino.h>
 
 #if !defined(SPI_INTERFACES_COUNT) ||                                          \
     (defined(SPI_INTERFACES_COUNT) && (SPI_INTERFACES_COUNT > 0))
 
-#ifndef Adafruit_BusIO_Register_h
-#define Adafruit_BusIO_Register_h
+#include <Adafruit_I2CDevice.h>
+#include <Adafruit_SPIDevice.h>
 
 typedef enum _Adafruit_BusIO_SPIRegType {
   ADDRBIT8_HIGH_TOREAD = 0,
@@ -79,7 +80,7 @@ private:
   Adafruit_BusIO_SPIRegType _spiregtype;
   uint16_t _address;
   uint8_t _width, _addrwidth, _byteorder;
-  uint8_t _buffer[4]; // we wont support anything larger than uint32 for
+  uint8_t _buffer[4]; // we won't support anything larger than uint32 for
                       // non-buffered read
   uint32_t _cached = 0;
 };
@@ -100,6 +101,5 @@ private:
   uint8_t _bits, _shift;
 };
 
-#endif // BusIO_Register_h
-
 #endif // SPI exists
+#endif // BusIO_Register_h
diff --git a/libraries/Adafruit_BusIO/Adafruit_I2CDevice.cpp b/libraries/Adafruit_BusIO/Adafruit_I2CDevice.cpp
index 1f72dbd..e95bb40 100755
--- a/libraries/Adafruit_BusIO/Adafruit_I2CDevice.cpp
+++ b/libraries/Adafruit_BusIO/Adafruit_I2CDevice.cpp
@@ -1,5 +1,4 @@
-#include <Adafruit_I2CDevice.h>
-#include <Arduino.h>
+#include "Adafruit_I2CDevice.h"
 
 //#define DEBUG_SERIAL Serial
 
@@ -14,6 +13,8 @@ Adafruit_I2CDevice::Adafruit_I2CDevice(uint8_t addr, TwoWire *theWire) {
   _begun = false;
 #ifdef ARDUINO_ARCH_SAMD
   _maxBufferSize = 250; // as defined in Wire.h's RingBuffer
+#elif defined(ESP32)
+  _maxBufferSize = I2C_BUFFER_LENGTH;
 #else
   _maxBufferSize = 32;
 #endif
@@ -36,6 +37,23 @@ bool Adafruit_I2CDevice::begin(bool addr_detect) {
   return true;
 }
 
+/*!
+ *    @brief  De-initialize device, turn off the Wire interface
+ */
+void Adafruit_I2CDevice::end(void) {
+  // Not all port implement Wire::end(), such as
+  // - ESP8266
+  // - AVR core without WIRE_HAS_END
+  // - ESP32: end() is implemented since 2.0.1 which is latest at the moment.
+  // Temporarily disable for now to give time for user to update.
+#if !(defined(ESP8266) ||                                                      \
+      (defined(ARDUINO_ARCH_AVR) && !defined(WIRE_HAS_END)) ||                 \
+      defined(ARDUINO_ARCH_ESP32))
+  _wire->end();
+  _begun = false;
+#endif
+}
+
 /*!
  *    @brief  Scans I2C for the address - note will give a false-positive
  *    if there's no pullups on I2C
@@ -90,7 +108,7 @@ bool Adafruit_I2CDevice::write(const uint8_t *buffer, size_t len, bool stop,
   _wire->beginTransmission(_addr);
 
   // Write the prefix data (usually an address)
-  if ((prefix_len != 0) && (prefix_buffer != NULL)) {
+  if ((prefix_len != 0) && (prefix_buffer != nullptr)) {
     if (_wire->write(prefix_buffer, prefix_len) != prefix_len) {
 #ifdef DEBUG_SERIAL
       DEBUG_SERIAL.println(F("\tI2CDevice failed to write"));
@@ -112,7 +130,7 @@ bool Adafruit_I2CDevice::write(const uint8_t *buffer, size_t len, bool stop,
   DEBUG_SERIAL.print(F("\tI2CWRITE @ 0x"));
   DEBUG_SERIAL.print(_addr, HEX);
   DEBUG_SERIAL.print(F(" :: "));
-  if ((prefix_len != 0) && (prefix_buffer != NULL)) {
+  if ((prefix_len != 0) && (prefix_buffer != nullptr)) {
     for (uint16_t i = 0; i < prefix_len; i++) {
       DEBUG_SERIAL.print(F("0x"));
       DEBUG_SERIAL.print(prefix_buffer[i], HEX);
@@ -127,22 +145,21 @@ bool Adafruit_I2CDevice::write(const uint8_t *buffer, size_t len, bool stop,
       DEBUG_SERIAL.println();
     }
   }
-  DEBUG_SERIAL.println();
-#endif
 
-#ifdef DEBUG_SERIAL
-  DEBUG_SERIAL.print("Stop: ");
-  DEBUG_SERIAL.println(stop);
+  if (stop) {
+    DEBUG_SERIAL.print("\tSTOP");
+  }
 #endif
 
   if (_wire->endTransmission(stop) == 0) {
 #ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.println();
     // DEBUG_SERIAL.println("Sent!");
 #endif
     return true;
   } else {
 #ifdef DEBUG_SERIAL
-    DEBUG_SERIAL.println("Failed to send!");
+    DEBUG_SERIAL.println("\tFailed to send!");
 #endif
     return false;
   }
diff --git a/libraries/Adafruit_BusIO/Adafruit_I2CDevice.h b/libraries/Adafruit_BusIO/Adafruit_I2CDevice.h
index d47714f..6bda7ba 100755
--- a/libraries/Adafruit_BusIO/Adafruit_I2CDevice.h
+++ b/libraries/Adafruit_BusIO/Adafruit_I2CDevice.h
@@ -1,19 +1,21 @@
-#include <Wire.h>
-
 #ifndef Adafruit_I2CDevice_h
 #define Adafruit_I2CDevice_h
 
+#include <Arduino.h>
+#include <Wire.h>
+
 ///< The class which defines how we will talk to this device over I2C
 class Adafruit_I2CDevice {
 public:
   Adafruit_I2CDevice(uint8_t addr, TwoWire *theWire = &Wire);
   uint8_t address(void);
   bool begin(bool addr_detect = true);
+  void end(void);
   bool detected(void);
 
   bool read(uint8_t *buffer, size_t len, bool stop = true);
   bool write(const uint8_t *buffer, size_t len, bool stop = true,
-             const uint8_t *prefix_buffer = NULL, size_t prefix_len = 0);
+             const uint8_t *prefix_buffer = nullptr, size_t prefix_len = 0);
   bool write_then_read(const uint8_t *write_buffer, size_t write_len,
                        uint8_t *read_buffer, size_t read_len,
                        bool stop = false);
diff --git a/libraries/Adafruit_BusIO/Adafruit_I2CRegister.h b/libraries/Adafruit_BusIO/Adafruit_I2CRegister.h
index 703e93b..186850f 100755
--- a/libraries/Adafruit_BusIO/Adafruit_I2CRegister.h
+++ b/libraries/Adafruit_BusIO/Adafruit_I2CRegister.h
@@ -1,7 +1,9 @@
-#include "Adafruit_BusIO_Register.h"
 #ifndef _ADAFRUIT_I2C_REGISTER_H_
 #define _ADAFRUIT_I2C_REGISTER_H_
 
+#include <Adafruit_BusIO_Register.h>
+#include <Arduino.h>
+
 typedef Adafruit_BusIO_Register Adafruit_I2CRegister;
 typedef Adafruit_BusIO_RegisterBits Adafruit_I2CRegisterBits;
 
diff --git a/libraries/Adafruit_BusIO/Adafruit_SPIDevice.cpp b/libraries/Adafruit_BusIO/Adafruit_SPIDevice.cpp
index f39627a..44a8f55 100755
--- a/libraries/Adafruit_BusIO/Adafruit_SPIDevice.cpp
+++ b/libraries/Adafruit_BusIO/Adafruit_SPIDevice.cpp
@@ -1,5 +1,4 @@
-#include <Adafruit_SPIDevice.h>
-#include <Arduino.h>
+#include "Adafruit_SPIDevice.h"
 
 #if !defined(SPI_INTERFACES_COUNT) ||                                          \
     (defined(SPI_INTERFACES_COUNT) && (SPI_INTERFACES_COUNT > 0))
@@ -7,7 +6,7 @@
 //#define DEBUG_SERIAL Serial
 
 /*!
- *    @brief  Create an SPI device with the given CS pin and settins
+ *    @brief  Create an SPI device with the given CS pin and settings
  *    @param  cspin The arduino pin number to use for chip select
  *    @param  freq The SPI clock frequency to use, defaults to 1MHz
  *    @param  dataOrder The SPI data order to use for bits within each byte,
@@ -29,7 +28,7 @@ Adafruit_SPIDevice::Adafruit_SPIDevice(int8_t cspin, uint32_t freq,
 }
 
 /*!
- *    @brief  Create an SPI device with the given CS pin and settins
+ *    @brief  Create an SPI device with the given CS pin and settings
  *    @param  cspin The arduino pin number to use for chip select
  *    @param  sckpin The arduino pin number to use for SCK
  *    @param  misopin The arduino pin number to use for MISO, set to -1 if not
@@ -70,18 +69,13 @@ Adafruit_SPIDevice::Adafruit_SPIDevice(int8_t cspin, int8_t sckpin,
   _dataMode = dataMode;
   _begun = false;
   _spiSetting = new SPISettings(freq, dataOrder, dataMode);
-  _spi = NULL;
+  _spi = nullptr;
 }
 
 /*!
  *    @brief  Release memory allocated in constructors
  */
-Adafruit_SPIDevice::~Adafruit_SPIDevice() {
-  if (_spiSetting) {
-    delete _spiSetting;
-    _spiSetting = nullptr;
-  }
-}
+Adafruit_SPIDevice::~Adafruit_SPIDevice() { delete _spiSetting; }
 
 /*!
  *    @brief  Initializes SPI bus and sets CS pin high
@@ -89,8 +83,10 @@ Adafruit_SPIDevice::~Adafruit_SPIDevice() {
  * init
  */
 bool Adafruit_SPIDevice::begin(void) {
-  pinMode(_cs, OUTPUT);
-  digitalWrite(_cs, HIGH);
+  if (_cs != -1) {
+    pinMode(_cs, OUTPUT);
+    digitalWrite(_cs, HIGH);
+  }
 
   if (_spi) { // hardware SPI
     _spi->begin();
@@ -118,7 +114,8 @@ bool Adafruit_SPIDevice::begin(void) {
 }
 
 /*!
- *    @brief  Transfer (send/receive) one byte over hard/soft SPI
+ *    @brief  Transfer (send/receive) a buffer over hard/soft SPI, without
+ * transaction management
  *    @param  buffer The buffer to send and receive at the same time
  *    @param  len    The number of bytes to transfer
  */
@@ -127,7 +124,7 @@ void Adafruit_SPIDevice::transfer(uint8_t *buffer, size_t len) {
     // hardware SPI is easy
 
 #if defined(SPARK)
-    _spi->transfer(buffer, buffer, len, NULL);
+    _spi->transfer(buffer, buffer, len, nullptr);
 #elif defined(STM32)
     for (size_t i = 0; i < len; i++) {
       _spi->transfer(buffer[i]);
@@ -255,7 +252,8 @@ void Adafruit_SPIDevice::transfer(uint8_t *buffer, size_t len) {
 }
 
 /*!
- *    @brief  Transfer (send/receive) one byte over hard/soft SPI
+ *    @brief  Transfer (send/receive) one byte over hard/soft SPI, without
+ * transaction management
  *    @param  send The byte to send
  *    @return The byte received while transmitting
  */
@@ -285,7 +283,38 @@ void Adafruit_SPIDevice::endTransaction(void) {
 }
 
 /*!
- *    @brief  Write a buffer or two to the SPI device.
+ *    @brief  Assert/Deassert the CS pin if it is defined
+ *    @param  value The state the CS is set to
+ */
+void Adafruit_SPIDevice::setChipSelect(int value) {
+  if (_cs != -1) {
+    digitalWrite(_cs, value);
+  }
+}
+
+/*!
+ *    @brief  Write a buffer or two to the SPI device, with transaction
+ * management.
+ *    @brief  Manually begin a transaction (calls beginTransaction if hardware
+ *            SPI) with asserting the CS pin
+ */
+void Adafruit_SPIDevice::beginTransactionWithAssertingCS() {
+  beginTransaction();
+  setChipSelect(LOW);
+}
+
+/*!
+ *    @brief  Manually end a transaction (calls endTransaction if hardware SPI)
+ *            with deasserting the CS pin
+ */
+void Adafruit_SPIDevice::endTransactionWithDeassertingCS() {
+  setChipSelect(HIGH);
+  endTransaction();
+}
+
+/*!
+ *    @brief  Write a buffer or two to the SPI device, with transaction
+ * management.
  *    @param  buffer Pointer to buffer of data to write
  *    @param  len Number of bytes from buffer to write
  *    @param  prefix_buffer Pointer to optional array of data to write before
@@ -294,29 +323,35 @@ void Adafruit_SPIDevice::endTransaction(void) {
  *    @return Always returns true because there's no way to test success of SPI
  * writes
  */
-bool Adafruit_SPIDevice::write(uint8_t *buffer, size_t len,
-                               uint8_t *prefix_buffer, size_t prefix_len) {
-  if (_spi) {
-    _spi->beginTransaction(*_spiSetting);
-  }
+bool Adafruit_SPIDevice::write(const uint8_t *buffer, size_t len,
+                               const uint8_t *prefix_buffer,
+                               size_t prefix_len) {
+  beginTransactionWithAssertingCS();
 
-  digitalWrite(_cs, LOW);
   // do the writing
-  for (size_t i = 0; i < prefix_len; i++) {
-    transfer(prefix_buffer[i]);
-  }
-  for (size_t i = 0; i < len; i++) {
-    transfer(buffer[i]);
-  }
-  digitalWrite(_cs, HIGH);
-
+#if defined(ARDUINO_ARCH_ESP32)
   if (_spi) {
-    _spi->endTransaction();
+    if (prefix_len > 0) {
+      _spi->transferBytes(prefix_buffer, nullptr, prefix_len);
+    }
+    if (len > 0) {
+      _spi->transferBytes(buffer, nullptr, len);
+    }
+  } else
+#endif
+  {
+    for (size_t i = 0; i < prefix_len; i++) {
+      transfer(prefix_buffer[i]);
+    }
+    for (size_t i = 0; i < len; i++) {
+      transfer(buffer[i]);
+    }
   }
+  endTransactionWithDeassertingCS();
 
 #ifdef DEBUG_SERIAL
   DEBUG_SERIAL.print(F("\tSPIDevice Wrote: "));
-  if ((prefix_len != 0) && (prefix_buffer != NULL)) {
+  if ((prefix_len != 0) && (prefix_buffer != nullptr)) {
     for (uint16_t i = 0; i < prefix_len; i++) {
       DEBUG_SERIAL.print(F("0x"));
       DEBUG_SERIAL.print(prefix_buffer[i], HEX);
@@ -338,7 +373,8 @@ bool Adafruit_SPIDevice::write(uint8_t *buffer, size_t len,
 }
 
 /*!
- *    @brief  Read from SPI into a buffer from the SPI device.
+ *    @brief  Read from SPI into a buffer from the SPI device, with transaction
+ * management.
  *    @param  buffer Pointer to buffer of data to read into
  *    @param  len Number of bytes from buffer to read.
  *    @param  sendvalue The 8-bits of data to write when doing the data read,
@@ -348,16 +384,10 @@ bool Adafruit_SPIDevice::write(uint8_t *buffer, size_t len,
  */
 bool Adafruit_SPIDevice::read(uint8_t *buffer, size_t len, uint8_t sendvalue) {
   memset(buffer, sendvalue, len); // clear out existing buffer
-  if (_spi) {
-    _spi->beginTransaction(*_spiSetting);
-  }
-  digitalWrite(_cs, LOW);
-  transfer(buffer, len);
-  digitalWrite(_cs, HIGH);
 
-  if (_spi) {
-    _spi->endTransaction();
-  }
+  beginTransactionWithAssertingCS();
+  transfer(buffer, len);
+  endTransactionWithDeassertingCS();
 
 #ifdef DEBUG_SERIAL
   DEBUG_SERIAL.print(F("\tSPIDevice Read: "));
@@ -376,9 +406,9 @@ bool Adafruit_SPIDevice::read(uint8_t *buffer, size_t len, uint8_t sendvalue) {
 }
 
 /*!
- *    @brief  Write some data, then read some data from SPI into another buffer.
- * The buffers can point to same/overlapping locations. This does not
- * transmit-receive at the same time!
+ *    @brief  Write some data, then read some data from SPI into another buffer,
+ * with transaction management. The buffers can point to same/overlapping
+ * locations. This does not transmit-receive at the same time!
  *    @param  write_buffer Pointer to buffer of data to write from
  *    @param  write_len Number of bytes from buffer to write.
  *    @param  read_buffer Pointer to buffer of data to read into.
@@ -388,17 +418,22 @@ bool Adafruit_SPIDevice::read(uint8_t *buffer, size_t len, uint8_t sendvalue) {
  *    @return Always returns true because there's no way to test success of SPI
  * writes
  */
-bool Adafruit_SPIDevice::write_then_read(uint8_t *write_buffer,
+bool Adafruit_SPIDevice::write_then_read(const uint8_t *write_buffer,
                                          size_t write_len, uint8_t *read_buffer,
                                          size_t read_len, uint8_t sendvalue) {
-  if (_spi) {
-    _spi->beginTransaction(*_spiSetting);
-  }
-
-  digitalWrite(_cs, LOW);
+  beginTransactionWithAssertingCS();
   // do the writing
-  for (size_t i = 0; i < write_len; i++) {
-    transfer(write_buffer[i]);
+#if defined(ARDUINO_ARCH_ESP32)
+  if (_spi) {
+    if (write_len > 0) {
+      _spi->transferBytes(write_buffer, nullptr, write_len);
+    }
+  } else
+#endif
+  {
+    for (size_t i = 0; i < write_len; i++) {
+      transfer(write_buffer[i]);
+    }
   }
 
 #ifdef DEBUG_SERIAL
@@ -432,11 +467,25 @@ bool Adafruit_SPIDevice::write_then_read(uint8_t *write_buffer,
   DEBUG_SERIAL.println();
 #endif
 
-  digitalWrite(_cs, HIGH);
+  endTransactionWithDeassertingCS();
 
-  if (_spi) {
-    _spi->endTransaction();
-  }
+  return true;
+}
+
+/*!
+ *    @brief  Write some data and read some data at the same time from SPI
+ * into the same buffer, with transaction management. This is basicaly a wrapper
+ * for transfer() with CS-pin and transaction management. This /does/
+ * transmit-receive at the same time!
+ *    @param  buffer Pointer to buffer of data to write/read to/from
+ *    @param  len Number of bytes from buffer to write/read.
+ *    @return Always returns true because there's no way to test success of SPI
+ * writes
+ */
+bool Adafruit_SPIDevice::write_and_read(uint8_t *buffer, size_t len) {
+  beginTransactionWithAssertingCS();
+  transfer(buffer, len);
+  endTransactionWithDeassertingCS();
 
   return true;
 }
diff --git a/libraries/Adafruit_BusIO/Adafruit_SPIDevice.h b/libraries/Adafruit_BusIO/Adafruit_SPIDevice.h
index 921030a..3a792c7 100755
--- a/libraries/Adafruit_BusIO/Adafruit_SPIDevice.h
+++ b/libraries/Adafruit_BusIO/Adafruit_SPIDevice.h
@@ -1,3 +1,6 @@
+#ifndef Adafruit_SPIDevice_h
+#define Adafruit_SPIDevice_h
+
 #include <Arduino.h>
 
 #if !defined(SPI_INTERFACES_COUNT) ||                                          \
@@ -5,9 +8,6 @@
 
 #include <SPI.h>
 
-#ifndef Adafruit_SPIDevice_h
-#define Adafruit_SPIDevice_h
-
 // some modern SPI definitions don't have BitOrder enum
 #if (defined(__AVR__) && !defined(ARDUINO_ARCH_MEGAAVR)) ||                    \
     defined(ESP8266) || defined(TEENSYDUINO) || defined(SPARK) ||              \
@@ -23,7 +23,7 @@ typedef enum _BitOrder {
   SPI_BITORDER_LSBFIRST = LSBFIRST,
 } BusIOBitOrder;
 
-#elif defined(ESP32) || defined(__ASR6501__)
+#elif defined(ESP32) || defined(__ASR6501__) || defined(__ASR6502__)
 
 // some modern SPI definitions don't have BitOrder enum and have different SPI
 // mode defines
@@ -39,7 +39,19 @@ typedef enum _BitOrder {
 typedef BitOrder BusIOBitOrder;
 #endif
 
-#if defined(__AVR__) || defined(TEENSYDUINO)
+#if defined(__IMXRT1062__) // Teensy 4.x
+// *Warning* I disabled the usage of FAST_PINIO as the set/clear operations
+// used in the cpp file are not atomic and can effect multiple IO pins
+// and if an interrupt happens in between the time the code reads the register
+//  and writes out the updated value, that changes one or more other IO pins
+// on that same IO port, those change will be clobbered when the updated
+// values are written back.  A fast version can be implemented that uses the
+// ports set and clear registers which are atomic.
+// typedef volatile uint32_t BusIO_PortReg;
+// typedef uint32_t BusIO_PortMask;
+//#define BUSIO_USE_FAST_PINIO
+
+#elif defined(__AVR__) || defined(TEENSYDUINO)
 typedef volatile uint8_t BusIO_PortReg;
 typedef uint8_t BusIO_PortMask;
 #define BUSIO_USE_FAST_PINIO
@@ -54,7 +66,7 @@ typedef uint32_t BusIO_PortMask;
     !defined(ARDUINO_ARCH_MBED) && !defined(ARDUINO_ARCH_RP2040)
 typedef volatile uint32_t BusIO_PortReg;
 typedef uint32_t BusIO_PortMask;
-#if not defined(__ASR6501__)
+#if !defined(__ASR6501__) && !defined(__ASR6502__)
 #define BUSIO_USE_FAST_PINIO
 #endif
 
@@ -77,16 +89,19 @@ public:
 
   bool begin(void);
   bool read(uint8_t *buffer, size_t len, uint8_t sendvalue = 0xFF);
-  bool write(uint8_t *buffer, size_t len, uint8_t *prefix_buffer = NULL,
-             size_t prefix_len = 0);
-  bool write_then_read(uint8_t *write_buffer, size_t write_len,
+  bool write(const uint8_t *buffer, size_t len,
+             const uint8_t *prefix_buffer = nullptr, size_t prefix_len = 0);
+  bool write_then_read(const uint8_t *write_buffer, size_t write_len,
                        uint8_t *read_buffer, size_t read_len,
                        uint8_t sendvalue = 0xFF);
+  bool write_and_read(uint8_t *buffer, size_t len);
 
   uint8_t transfer(uint8_t send);
   void transfer(uint8_t *buffer, size_t len);
   void beginTransaction(void);
   void endTransaction(void);
+  void beginTransactionWithAssertingCS();
+  void endTransactionWithDeassertingCS();
 
 private:
   SPIClass *_spi;
@@ -94,6 +109,7 @@ private:
   uint32_t _freq;
   BusIOBitOrder _dataOrder;
   uint8_t _dataMode;
+  void setChipSelect(int value);
 
   int8_t _cs, _sck, _mosi, _miso;
 #ifdef BUSIO_USE_FAST_PINIO
@@ -103,5 +119,5 @@ private:
   bool _begun;
 };
 
-#endif // Adafruit_SPIDevice_h
 #endif // has SPI defined
+#endif // Adafruit_SPIDevice_h
diff --git a/libraries/Adafruit_BusIO/CMakeLists.txt b/libraries/Adafruit_BusIO/CMakeLists.txt
new file mode 100755
index 0000000..880b1aa
--- /dev/null
+++ b/libraries/Adafruit_BusIO/CMakeLists.txt
@@ -0,0 +1,11 @@
+# Adafruit Bus IO Library
+# https://github.com/adafruit/Adafruit_BusIO
+# MIT License
+
+cmake_minimum_required(VERSION 3.5)
+
+idf_component_register(SRCS "Adafruit_I2CDevice.cpp" "Adafruit_BusIO_Register.cpp" "Adafruit_SPIDevice.cpp" 
+                       INCLUDE_DIRS "."
+                       REQUIRES arduino)
+
+project(Adafruit_BusIO)
diff --git a/libraries/Adafruit_BusIO/README.md b/libraries/Adafruit_BusIO/README.md
index 3fc8a1f..1cc06a1 100755
--- a/libraries/Adafruit_BusIO/README.md
+++ b/libraries/Adafruit_BusIO/README.md
@@ -1,7 +1,7 @@
 # Adafruit Bus IO Library [![Build Status](https://github.com/adafruit/Adafruit_BusIO/workflows/Arduino%20Library%20CI/badge.svg)](https://github.com/adafruit/Adafruit_BusIO/actions)
 
 
-This is a helper libary to abstract away I2C & SPI transactions and registers
+This is a helper library to abstract away I2C & SPI transactions and registers
 
 Adafruit invests time and resources providing this open source code, please support Adafruit and open-source hardware by purchasing products from Adafruit!
 
diff --git a/libraries/Adafruit_BusIO/component.mk b/libraries/Adafruit_BusIO/component.mk
new file mode 100755
index 0000000..049f190
--- /dev/null
+++ b/libraries/Adafruit_BusIO/component.mk
@@ -0,0 +1 @@
+COMPONENT_ADD_INCLUDEDIRS = .
diff --git a/libraries/Adafruit_BusIO/examples/spi_register_bits/spi_register_bits.ino b/libraries/Adafruit_BusIO/examples/spi_register_bits/spi_register_bits.ino
index ff21fb7..e70a17b 100755
--- a/libraries/Adafruit_BusIO/examples/spi_register_bits/spi_register_bits.ino
+++ b/libraries/Adafruit_BusIO/examples/spi_register_bits/spi_register_bits.ino
@@ -139,7 +139,7 @@ void setup() {
 
 void loop() {
   #if (defined( MAX31865_READY_PIN ) && (MAX31865_1_READY_PIN != -1))
-    // Is converstion ready?
+    // Is conversion ready?
     if (!digitalRead(MAX31865_READY_PIN))
   #else
     // Warant conversion is ready.
diff --git a/libraries/Adafruit_BusIO/library.properties b/libraries/Adafruit_BusIO/library.properties
index 4e726a3..54c2366 100755
--- a/libraries/Adafruit_BusIO/library.properties
+++ b/libraries/Adafruit_BusIO/library.properties
@@ -1,5 +1,5 @@
 name=Adafruit BusIO
-version=1.9.3
+version=1.12.0
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=This is a library for abstracting away UART, I2C and SPI interfacing