CircuitPython, a MicroPython derivative, implements Python 3.x on microcontrollers such as the SAMD21 and ESP8266.
This project is in beta. Most APIs should be stable going forward.
Designed for CircuitPython¶
See CONTRIBUTING.md for full guidelines but please be aware that by contributing to this project you are agreeing to the Code of Conduct. Contributors who follow the Code of Conduct are welcome to submit pull requests and they will be promptly reviewed by project admins. Please join the Gitter chat or Discord too.
Differences from MicroPython¶
- includes a port for Atmel SAMD21 (Commonly known as M0 in Adafruit product names.)
- supports only Atmel SAMD21 and ESP8266 ports.
- tracks MicroPython's releases (not master).
- The order that files are run and the state that is shared between them.
CircuitPython's goal is to clarify the role of each file and make each
file independent from each other.
settings.py) runs only once on start up before USB is initialized. This lays the ground work for configuring USB at startup rather than it being fixed. Since serial is not available, output is written to
main.py) is run after every reload until it finishes or is interrupted. After it is done running, the vm and hardware is reinitialized. This means you cannot read state from
code.pyin the REPL anymore. CircuitPython's goal for this change includes reduce confusion about pins and memory being used.
code.pythe REPL can be entered by pressing any key. It no longer shares state with
code.pyso it is a fresh vm.
- Autoreload state will be maintained across reload.
- Adds a safe mode that does not run user code after a hard crash or brown out. The hope is that this will make it easier to fix code that causes nasty crashes by making it available through mass storage after the crash. A reset (the button) is needed after its fixed to get back into normal mode.
- No module aliasing. (
utimeare not available as
randomare CPython compatible.
storagemodule which manages file system mounts. (Functionality from
- Modules with a CPython counterpart, such as
random, are strict subsets of their CPython version. Therefore, code from CircuitPython is runnable on CPython but not necessarily the reverse.
- tick count is available as
- RGB status LED
- Auto-reload after file write over mass storage. (Disable with
- Wait state after boot and main run, before REPL.
- Main is one of these:
- Boot is one of these:
Here is an overview of the top-level source code directories.
The core code of MicroPython is shared amongst ports including CircuitPython:
docsHigh level user documentation in Sphinx reStructuredText format.
driversExternal device drivers written in Python.
examplesA few example Python scripts.
extmodShared C code used in multiple ports' modules.
libShared core C code including externally developed libraries such as FATFS.
logoThe MicroPython logo.
mpy-crossA cross compiler that converts Python files to byte code prior to being run in MicroPython. Useful for reducing library size.
pyCore Python implementation, including compiler, runtime, and core library.
shared-bindingsShared definition of Python modules, their docs and backing C APIs. Ports must implement the C API to support the corresponding module.
shared-moduleShared implementation of Python modules that may be based on
testsTest framework and test scripts.
toolsVarious tools, including the pyboard.py module.
Ports include the code unique to a microcontroller line and also variations based on the board.
atmel-samdSupport for SAMD21 based boards such as Arduino Zero, Adafruit Feather M0 Basic, and Adafruit Feather M0 Bluefruit LE.
bare-armA bare minimum version of MicroPython for ARM MCUs.
cc3200Support for boards based CC3200 from TI such as the WiPy 1.0.
esp8266Support for boards based on ESP8266 WiFi modules such as the Adafruit Feather HUZZAH.
minimalA minimal MicroPython port. Start with this if you want to port MicroPython to another microcontroller.
pic16bitSupport for 16-bit PIC microcontrollers.
qemu-armSupport for ARM emulation through QEMU.
stmhalSupport for boards based on STM32 microcontrollers including the MicroPython flagship PyBoard.
teensySupport for the Teensy line of boards such as the Teensy 3.1.
unixSupport for UNIX.
windowsSupport for Windows.
zephyrSupport for Zephyr, a real-time operating system by the Linux Foundation.
CircuitPython only maintains the
esp8266 ports. The
rest are here to maintain compatibility with the
MicroPython parent project.