kopia lustrzana https://github.com/peterhinch/micropython-samples
Add index and sequence check.
Peter Hinch
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README.md
238
README.md
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@ -2,61 +2,82 @@
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A place for assorted code ideas for MicroPython. Most are targeted at the
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Pyboard variants.
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# Installing MicroPython libraries
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1. [Installation guides](./README.md#1-installation-guides)
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1.1 [Installing MicroPython libraries](./README.md#11-installing-micropython-libraries)
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1.2 [Fastbuild](./README.md#12-fastbuild) Build scripts and udev rules
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1.3 [Installing PicoWeb](./README.md#13-installing-picoweb)
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1.4 [Buildcheck](./README.md#14-buildcheck) Check firmware build date
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2. [Hardware information and drivers](./README.md#2-hardware-information-and-drivers)
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2.1 [ESP32](./README.md#21-esp32)
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2.2 [SSD1306](./README.md#22-ssd1306) Write large fonts to the SSD1306
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2.3 [Pyboard D](./README.md#23-pyboard-d) Assorted scraps of information
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2.4 [DS3231 precision RTC](./README.md#24-ds3231-precision-rtc) Use cheap hardware to calibrate Pyboard RTC
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3. [Essays](./README.md#3-essays) General thoughts
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3.1 [Resilient](./README.md#31-resilient) A guide to writing resilient WiFi code
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3.2 [Serialisation](./README.md#32-serialisation) MicroPython's four serialisation libraries
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3.3 [Measurement of relative timing and phase of fast analog signals](./README.md#33-measurement-of-relative-timing-and-phase-of-fast-analog-signals)
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4. [Code samples](./README.md#4-code-samples) Samples prefixed Pyboard are Pyboard specific
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4.1 [Pyboard Mutex](./README.md#41-pyboard-mutex) Share data between threads and ISR's.
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4.2 [Pyboard watchdog](./README.md#42-pyboard-watchdog) Access a Pyboard hardware WDT
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4.3 [Software Watchdog](./README.md#43-software-watchdog) Cross-platform soft WDT
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4.4 [Reverse](./README.md#44-reverse) Reversal algorithms for bytearrays
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4.5 [Timed function](./README.md#45-timed-function)
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4.6 [ESP8266 MQTT benchmark](./README.md#46-esp8266-mqtt-benchmark) Test performance of official library
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4.7 [Rotary incremental encoder](./README.md#47-rotary-incremental-encoder) Fast, simple, proven algorithm
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4.8 [A pseudo random number generator](./README.md#48-a-pseudo-random-number-generator)
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4.9 [Verifying incrementing sequences](./README.md#49-verifying-incrementing-sequences)
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4.10 [Bitmaps](./README.md#410-bitmaps) Non-allocating ways to access bitmaps
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4.11 [Functors and singletons](./README.md#411-functors-and-singletons)
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4.12 [A Pyboard power meter](./README.md#412-a-pyboard-power-meter)
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# 1. Installation guides
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## 1.1 Installing MicroPython libraries
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This is more involved since the advent of the pycopy fork of MicroPython.
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[This doc](./micropip/README.md) describes the issues and provides a utility
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to simplify installation for users of official MicroPython firmware.
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# Fastbuild
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## 1.2 Fastbuild
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Scripts for building MicroPython for various target hardware types and for
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updating your local source. Now detects and builds for Pyboard D. See [docs](./fastbuild/README.md)
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updating your local source. Now detects and builds for Pyboard D. See
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[docs](./fastbuild/README.md)
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# ESP32
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## 1.3 Installing PicoWeb
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Paul Sokolovsk's [PicoWeb](https://github.com/pfalcon/picoweb) requires his
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fork of MicroPython.
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Some time ago I was asked what was involved to install it on official firmware.
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Changes were minor. However it should be stressed that while the version here
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works, it is not up to date. See the [Easy installation](./PICOWEB.md) guide.
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PR's with updated versions of PicoWeb are welcome.
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## 1.4 Buildcheck
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Raise an [exception](./buildcheck/buildcheck.py) if a firmware build is earlier
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than a given date.
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# 2. Hardware information and drivers
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## 2.1 ESP32
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Pinout diagram for the reference board with notes and warnings about reserved
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pins etc. See [this doc](./ESP32/ESP32-Devkit-C-pinout.pdf).
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# PicoWeb
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[Easy installation](./PICOWEB.md) guide. Simplify installing this on
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MicroPython hardware platforms under official MicroPython firmware.
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# Serialisation
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[A discussion](./SERIALISATION.md) of the need for serialisation and of the
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relative characteristics of four libraries available to MicroPython. Includes a
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tutorial on a Protocol Buffer library.
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# SSD1306
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## 2.2 SSD1306
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A means of rendering multiple larger fonts to the SSD1306 OLED display. The
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`Writer` class which performs this has been substantially improved and may now
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be found as part of [this repository](https://github.com/peterhinch/micropython-font-to-py).
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# mutex
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## 2.3 Pyboard D
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A class providing mutual exclusion enabling interrupt handlers and the main
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program to access shared data in a manner which ensures data integrity.
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Assorted [information](./pyboard_d/README.md) not yet in the official docs).
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# watchdog
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Access the simpler of the Pyboard's watchdog timers.
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# software watchdog (soft_wdt)
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A software watchdog timer with a fixed or variable timeout. Supports temporary
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suspension and permanent cancellation. The latter can be useful when debugging
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code to prevent a machine reboot when the application fails, terminates or is
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interrupted with ctrl-c. See code and comments in swdt_tests.py.
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# reverse
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Fast reverse a bytearray in Arm Thumb assembler.
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Python code to bit-reverse (fast-ish) 8, 16 and 32 bit words.
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# DS3231
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## 2.4 DS3231 precision RTC
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This is a low cost precision battery backed real time clock (RTC) accurate to
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+-2 minutes/year. Two drivers are provided, one portable across platforms and
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@ -67,50 +88,90 @@ from the DS3231. Calibration to high precision may be achieved in five minutes.
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The drivers are [documented here](./DS3231/README.md).
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# Buildcheck
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# 3. Essays
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Raise an exception if a firmware build is earlier than a given date.
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## 3.1 Resilient
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# timed_function
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A [guide](./resilient/README.md) to writing reliable ESP8266 networking code.
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Probably applies to other WiFi connected MicroPython devices.
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Time a function's execution using a decorator. Also a way to implement timeouts
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using a closure.
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## 3.2 Serialisation
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# ESP8266 (MQTT benchmark)
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[A discussion](./SERIALISATION.md) of the need for serialisation and of the
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relative characteristics of four libraries available to MicroPython. Includes a
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tutorial on a Protocol Buffer library.
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benchmark.py Tests the performance of MQTT by periodically publishing while
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subscribed to the same topic. Measures the round-trip delay. Adapt to suit your
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## 3.3 Measurement of relative timing and phase of fast analog signals
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This describes ways of using the Pyboard to perform precision measurements of
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analog signals of up to around 50KHz. It is documented [here](./phase/README.md).
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# 4. Code samples
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## 4.1 Pyboard mutex
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A [class](./mutex/README.md) providing mutual exclusion enabling hard interrupt
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handlers and the main program to access shared data in a manner which ensures
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data integrity.
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## 4.2 Pyboard watchdog
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[Access](./watchdog/wdog.py) the simpler of the Pyboard's watchdog timers.
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## 4.3 Software watchdog
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A [software watchdog](./soft_wdt/soft_wdt.py) timer with a fixed or variable
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timeout. Supports temporary suspension and permanent cancellation. The latter
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can be useful when debugging code to prevent a machine reboot when the
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application fails, terminates or is interrupted with ctrl-c. See code and
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comments in [the test script](./soft_wdt/swdt_tests.py).
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## 4.4 Reverse
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Fast [reverse](./reverse/reverse.py) a bytearray in Arm Thumb assembler.
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Also includes cross-platform Python code to bit-reverse (fast-ish) 8, 16 and 32
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bit words.
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## 4.5 Timed function
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Time a function's execution using a [decorator](./timed_function/timed_func.py)
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and implement timeouts using a [closure](./timed_function/timeout.py).
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## 4.6 ESP8266 MQTT benchmark
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[This benchmark](./ESP8266/benchmark.py) tests the performance of MQTT by
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periodically publishing while subscribed to the same topic. Measures the
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round-trip delay. Uses the official `umqtt.simple` library. Adapt to suit your
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server address and desired QOS (quality of service, 0 and 1 are supported).
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After 100 messages reports maximum and minimum delays.
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`conn.py` Connect in station mode using saved connection details where possible.
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[This connect utility](./esp32/conn.py) connects in station mode using saved
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connection details where possible.
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# resilient
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## 4.7 Rotary Incremental Encoder
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A guide to writing reliable ESP8266 networking code. Probably applies to other
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WiFi connected MicroPython devices, but reliable ones are thin on the ground.
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Classes for handling incremental rotary position encoders. Note Pyboard timers
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can do this in hardware. These samples cater for cases where that solution
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can't be used. The [encoder_timed.py](./encoders/encoder_timed.py) sample
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provides rate information by timing successive edges. In practice this is
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likely to need filtering to reduce jitter caused by imperfections in the
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encoder geometry.
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# Rotary Incremental Encoder
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Classes for handling incremental rotary position encoders. Note that the Pyboard
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timers can do this in hardware. These samples cater for cases where that
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solution can't be used. The `encoder_timed.py` sample provides rate information by
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timing successive edges. In practice this is likely to need filtering to reduce
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jitter caused by imperfections in the encoder geometry.
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There are other algorithms but this is the simplest and fastest I've encountered.
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There are other algorithms but this is the simplest and fastest I've
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encountered.
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These were written for encoders producing TTL outputs. For switches, adapt the
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pull definition to provide a pull up or pull down as required.
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The `encoder.portable.py` version should work on all MicroPython platforms.
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Tested on ESP8266. Note that interrupt latency on the ESP8266 limits
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performance. ESP32 has similar limitations.
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The [encoder_portable.py](./encoders/encoder_portable) version should work on
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all MicroPython platforms. Tested on ESP8266. Note that interrupt latency on
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the ESP8266 limits performance. ESP32 has similar limitations.
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# A pseudo random number generator
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## 4.8 A pseudo random number generator
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On the Pyboard V1.1, true random numbers may be generated rapidly with pyb.rng()
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which uses a hardware random number generator on the microcontroller.
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On the Pyboard V1.1, true random numbers may be generated rapidly with
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`pyb.rng()` which uses a hardware random number generator on the
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microcontroller.
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There are two use cases for the pseudo random number generator. Firstly on
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platforms lacking a hardware generator (e.g. the Pyboard Lite). And secondly
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@ -119,28 +180,53 @@ number generator is seeded with an arbitrary initial value. On each call to the
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function it will return a random number, but (given the same seed) the sequence
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of numbers following initialisation will always be the same.
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See the code for usage and timing documentation.
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See [random.py](./random/random.py) for usage and timing documentation.
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# Measurement of relative timing and phase of fast analog signals
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## 4.9 Verifying incrementing sequences
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This describes ways of using the Pyboard to perform precision measurements of
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analog signals of up to around 50KHz. It is documented [here](./phase/README.md).
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# bitmap: bool arrays and sets of integers
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Classes for non-allocating handling of sets of small integers and small arrays
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of booleans. Legal member values for a set and array index values are
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constrained to 0 <= value <= max_value where max_value is a constructor arg.
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The set and the array are different ways of viewing a bitmap implemented as a
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bytearray: e.g. if max_value is 255 the bytearray occupies 32 bytes allocated by
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the constructor.
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## 4.10 Bitmaps
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# Functors and singletons
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A bitmap stored in a pre-allocated, fixed size bytearray may be viewed in two
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ways:
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1. As a set of positive integers whose values are constrained within limits.
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2. As a fixed size one dimensional array of booleans.
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These views provide a Pythonic interface while retaining the non-allocating
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performance advantage relative to native sets and lists.
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The file [bitmap.py](./bitmap/bitmap.py) offers classes supporting these views.
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The constraint `0 <= value <= max_value` applies where `max_value` is a
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constructor arg. The `max_value` arg defines the size of the underlying
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bytearray. For example if `max_value` is 255, the bytearray will use 32 bytes.
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The constraint applies to member values of a set, and to index values of a
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boolean array.
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These classes are lightweight. For example the `IntSet` class does not include
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all the dunder (magic) methods required to match the native `set` class. These
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may readily be added as required.
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## 4.11 Functors and singletons
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Two simple class decorators for objects useful in hardware interfacing.
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Documented [here](./functor_singleton/README.md).
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# A design for a hardware power meter
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Singletons denote classes for which only a single instance will ever occur.
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They are contentious in some circles, on the grounds that the single instance
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guarantee may be violated in a specification change. They can be useful in
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hardware contexts where a chip design is unlikely suddenly to change.
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Singletons denoting hardware interfaces avoid globals and the need to pass
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references around.
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A functor is a class which is accessed via function call syntax. There is only
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one instance, like a singleton. Initial access calls the constructor, with
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subsequent accesses being via `__call__`. As an object it can retain state. As
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an example, a functor might have a continuously running task: successive calls
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modify the behaviour of the task.
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# 4.12 A pyboard power meter
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This uses a Pyboard to measure the power consumption of mains powered devices.
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Unlike simple commercial devices it performs a true vector (phasor) measurement
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@ -0,0 +1,46 @@
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# check_mid.py Check a sequence of incrementing message ID's.
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# Released under the MIT licence. See LICENSE.
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# Copyright (C) Peter Hinch 2020
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# For use in test scripts: message ID's increment without bound rather
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# than modulo N. Assumes message ID's start with 0 or 1.
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# Missing and duplicate message counter. Handles out-of-order messages.
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# Out of order messages will initially be missing to arrive later.
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# The most recent n message ID's are therefore not checked. If a
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# message is missing after n have been received, it is assumed lost.
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class CheckMid:
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def __init__(self, buff=5):
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self._buff = buff
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self._mids = set()
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self.miss = 0 # Count missing message ID's
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self.dupe = 0 # Duplicates
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self.oord = 0 # Received out of order
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self.bcnt = 0 # Reboot count
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def __call__(self, mid):
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mids = self._mids
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if mid <= 1 and len(mids) > 1: # Target has rebooted
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self._mids.clear()
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self.miss = 0
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self.dupe = 0
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self.oord = 0
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self.bcnt += 1
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if mid in mids:
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self.dupe += 1
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elif mids and mid < max(mids):
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self.oord += 1
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mids.add(mid)
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if len(mids) > self._buff:
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oldest = min(mids)
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mids.remove(oldest)
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self.miss += min(mids) - oldest - 1
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# Usage/demo
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#cm = CheckMid()
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#s1 = (1,2,3,4,5,8,9,10,11,12,13,17,17,16,18,19,20,21,22,23,24,29,28,27,26,30,31,32,33,34,35,36)
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#for x in s1:
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#cm(x)
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#print(cm.dupe, cm.miss, cm.oord, cm.bcnt)
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