MicroPython - Python for microcontrollers. More...

Detailed Description

MicroPython - Python for microcontrollers.

MicroPython is a lean and efficient implementation of the Python 3 programming language that includes a small subset of the Python standard library and is optimised to run on microcontrollers and in constrained environments.

See also: The MicroPython Project Website has more information about the project, usage and limitations: https://micropython.org

Status

MicroPython on RIOT has to be considered experimental. While the basic interpreter works fairly well on native and Cortex-M, it has not seen much testing.

Hardware compatibility

The RIOT OS port targets microcontrollers that have at least 16 KiB of RAM and 256 KiB of flash. Although MicroPython has many different tuning options, the requirement provides a decent out-of-the-box experience.

Configuration options

Use the following environment variables in the application Makefile or from the command line to configure MicroPython:

MP_RIOT_HEAPSIZE: heap size for MicroPython, in bytes. Defaults to 16 KiB.

Example on the command line:

MP_RIOT_HEAPSIZE=2048 make -C examples/lang_support/community/micropython

Implementation details

This package builds upstream MicroPython. The RIOT port itself lives in this package's contrib/ directory. It is compiled with MicroPython's own build system, and is based on MicroPython's ports/minimal with some extra modules enabled.

Interrupts

MicroPython will handle interrupts in as scheduled callbacks, so they run in the MicroPython's thread context. This means an interrupt will have a bit of latency before the callback is executed.

MicroPython's test suite

It is possible to run MicroPython's test suite for testing this port.

Steps:

make -C examples/lang_support/community/micropython flash mpy-tests

The default baud rate is 115200. The test will switch the interpreter into raw REPL mode for testing. Expect some tests to fail, depending on the enabled features and configured heap size.

MicroPython modules

MicroPython has a large number of built-in modules available. See the port configuration file contrib/mpconfigport.h for more details on the exact set of modules enabled in this port.

The following modules are built-in, but use RIOT's own APIs internally:

machine - ADC, GPIO, SPI and more
time - time functions

RIOT specific modules

The following RIOT specific modules are available:

riot - RIOT-specific functions
xtimer - xtimer subsystem

You can import these modules and then use help(<module name>) to introspect the available functions.

thread_getpid()

import riot

print(riot.thread_getpid())

print

void print(const char *s, size_t n)

Print string to stdout.

xtimer

import xtimer
 
a = 0
def inc_a():
  global a
  a += 1
 
t = xtimer.xtimer(inc_a)
t.set(100000)
print(a)

The callback does not run in interrupt context. When the timer fires, its execution is deferred via MicroPython's scheduler and runs in thread context. See the implementation details section for more information.

How to use

See examples/lang_support/community/micropython for example code.

Files
file	modmachine.h
	MicroPython machine module type declarations.

file	mp_riot.h
	MicroPython RIOT port core glue declarations.

file	mpconfigport.h
	MicroPython port configuration for RIOT.

file	mphalport.h
	MicroPython HAL port definitions for RIOT.

file	qstrdefsport.h.in
	Port-specific MicroPython qstr definitions.

file	micropython.h
	MicroPython RIOT specific API.