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circuitpython/esp8266/README.md
Damien George 56845b6aff esp8266/README: Describe how to build mpy-cross.
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MicroPython port to ESP8266

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

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

Currently implemented 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).

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.

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 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. To specify another, use, eg:

$ make PORT=/dev/ttyUSB0 deploy

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

First start

Serial prompt

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

  • Baudrate: 115200

WiFi

Initally, 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.

WebREPL

Python prompt over WiFi, connecting through a browser.

Please follow the instructions there.

More detailed instructions can be found at http://docs.micropython.org/en/latest/esp8266/esp8266/tutorial/intro.html

Troubleshooting

While the port is still in alpha, 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.