I have never talked about micropython before. Recently I started using it a lot so I wanted to let you know, too. I use Arch linux but I am sure that these tools are available for other Linux distros as well. I am running micropython on ESP8266 (Wemos D1 mini board).

Install tools (esptool, adafruit-ampy)

You can use conda or whatever tools you like to work with when preparing your python environment.

As always I use virtualenv to setup a local development environment:

$ virtualenv venv
$ . ./venv/bin/activate

$ pip install -r requirements.txt

Upload micropython

I use the esptool.py to upload the micropython firmware to the microcontroller.

To clean all existing stuff from the ESP8266:

$ esptool.py --port /dev/ttyUSB0 erase_flash

Get the micropython firmware here.

$ esptool.py  --port /dev/ttyUSB0 --baud 460800 write_flash -fm dio --flash_size=detect 0 esp8266-20191220-v1.12.bin

Terminal

Normally during development I power my wemos D1 mini boards via a USB mini cable. Conveniently a serial connection is available using the same cable so I can check what is going on on the board.

I use picocom (because screen gives me some trouble):

$ picocom --baud 115200 /dev/ttyUSB0

exit with CTRL-A-X

Work with the micropython board

To upload your scripts to the board you have at least two options available:

  • micropython pyboard.py
  • adafruit-ampy

I am currently using adafruit-ampy because it has the nicer command line.

To install ampy:

$ pip install adafruit-ampy

Pinout

Careful the pin numbers used in micropython might differ to what you are used to. Please check in advance:

https://micropython-on-wemos-d1-mini.readthedocs.io/en/latest/basics.html

Sample “main.py”

from time import sleep
from machine import Pin

led1 = Pin(4, Pin.OUT)
led2 = Pin(5, Pin.OUT)
while True: 
    led1.on()
    led2.off()
    sleep(0.5)
    led1.off()
    led2.on()
    sleep(0.5)

Run the sample script

The ‘run’ command runs the program on the ESP8266 one time only.

$ ampy --port /dev/ttyUSB0 run main.py

Install the script on the board

Once you reset or power down the board the previous run ends and your script is gone. To make it more permanent (and install the script on the board) do the following:

$ ampy --port /dev/ttyUSB0 put main_blinker.py main.py

You can use picocom to check what is going on:

$ picocom --baud 115200 /dev/ttyUSB0

exit with CTRL-A-X

If you follow the convention to name the script “main.py” for uploading that is all you have to do. The main.py script is installed on the microcontroller. After a reset it starts running.

Removing the script is simple, too:

$ ampy --port /dev/ttyUSB0 rm main.py

Production setup

What I have shown to you above is the “development setup”. Of cause you would want to have a firmware without python console prohibiting the upload of files etc.

please find more information about a production build here.

Best, Mark

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