MicroPython port to ESP8266

This is an experimental port of MicroPython for the WiFi modules based on Espressif ESP8266 chip.

WARNING: The port is experimental and many APIs are subject to change.

Supported features include:

  • REPL (Python prompt) over UART0.
  • Garbage collector, exceptions.
  • Unicode support.
  • Builtin modules: gc, array, collections, io, struct, sys, esp, network, many more.
  • Arbitrary-precision long integers and 30-bit precision floats.
  • WiFi support.
  • Sockets using modlwip.
  • GPIO and bit-banging I2C, SPI support.
  • 1-Wire and WS2812 (aka Neopixel) protocols support.
  • Internal filesystem using the flash.
  • WebREPL over WiFi from a browser (clients at https://github.com/micropython/webrepl).
  • Modules for HTTP, MQTT, many other formats and protocols via https://github.com/micropython/micropython-lib .

Work-in-progress documentation is available at http://docs.micropython.org/en/latest/esp8266/ .

Build instructions

The tool chain required for the build is the OpenSource ESP SDK, which can be found at https://github.com/pfalcon/esp-open-sdk. Clone this repository and run make in its directory to build and install the SDK locally. Make sure to add toolchain bin directory to your PATH. Read esp-open-sdk’s README for additional important information on toolchain setup.

Travis builds, including releases are actually built using a specific esp-open-sdk binary. The location of the binary can be seen in the .travis.yml in the top-level directory of CircuitPython. This may be ahead of or behind the pfalcon repository, depending on the specific needs of CircuitPython. If your local system is binary-compatible with Travis (most Ubuntu and Debian based systems are), you can download the binary and skip building it locally.

Add the external dependencies to the MicroPython repository checkout:

$ git submodule update --init

See the README in the repository root for more information about external dependencies.

The MicroPython cross-compiler must be built to pre-compile some of the built-in scripts to bytecode. This can be done using:

$ make -C mpy-cross

Then, to build MicroPython for the ESP8266, just run:

$ cd ports/esp8266
$ make axtls
$ make

This will produce binary images in the build/ subdirectory. If you install MicroPython to your module for the first time, or after installing any other firmware, you should erase flash completely:

esptool.py --port /dev/ttyXXX erase_flash

Erase flash also as a troubleshooting measure, if a module doesn’t behave as expected.

To flash MicroPython image to your ESP8266, use:

$ make deploy

This will use the esptool.py script to download the images. You must have your ESP module in the bootloader mode, and connected to a serial port on your PC. The default serial port is /dev/ttyACM0, flash mode is qio and flash size is detect (auto-detect based on Flash ID). To specify other values, use, eg (note that flash size is in megabits):

$ make PORT=/dev/ttyUSB0 FLASH_MODE=qio FLASH_SIZE=32m deploy

The image produced is build/firmware-combined.bin, to be flashed at 0x00000.

512KB FlashROM version

The normal build described above requires modules with at least 1MB of FlashROM onboard. There’s a special configuration for 512KB modules, which can be built with make 512k. This configuration is highly limited, lacks filesystem support, WebREPL, and has many other features disabled. It’s mostly suitable for advanced users who are interested to fine-tune options to achieve a required setup. If you are an end user, please consider using a module with at least 1MB of FlashROM.

First start

Be sure to change ESP8266’s WiFi access point password ASAP, see below.

Serial prompt

You can access the REPL (Python prompt) over UART (the same as used for programming).

  • Baudrate: 115200

Run help() for some basic information.

WiFi

Initially, the device configures itself as a WiFi access point (AP).

  • ESSID: MicroPython-xxxxxx (x’s are replaced with part of the MAC address).
  • Password: micropythoN (note the upper-case N).
  • IP address of the board: 192.168.4.1.
  • DHCP-server is activated.
  • Please be sure to change the password to something non-guessable immediately. help() gives information how.

WebREPL

Python prompt over WiFi, connecting through a browser.

  • Hosted at http://micropython.org/webrepl.
  • GitHub repository https://github.com/micropython/webrepl. Please follow the instructions there.

upip

The ESP8266 port comes with builtin upip package manager, which can be used to install additional modules (see the main README for more information):

>>> import upip
>>> upip.install("micropython-pystone_lowmem")
[...]
>>> import pystone_lowmem
>>> pystone_lowmem.main()

Downloading and installing packages may requite a lot of free memory, if you get an error, retry immediately after the hard reset.

Documentation

More detailed documentation and instructions can be found at http://docs.micropython.org/en/latest/esp8266/ , which includes Quick Reference, Tutorial, General Information related to ESP8266 port, and to MicroPython in general.

Troubleshooting

While the port is in beta, it’s known to be generally stable. If you experience strange bootloops, crashes, lockups, here’s a list to check against:

  • You didn’t erase flash before programming MicroPython firmware.
  • Firmware can be occasionally flashed incorrectly. Just retry. Recent esptool.py versions have –verify option.
  • Power supply you use doesn’t provide enough power for ESP8266 or isn’t stable enough.
  • A module/flash may be defective (not unheard of for cheap modules).

Please consult dedicated ESP8266 forums/resources for hardware-related problems.

Additional information may be available by the documentation links above.