From 0cc7c910c4d3d432f50b75865d5d5f1d293a9207 Mon Sep 17 00:00:00 2001 From: Mitja Felicijan Date: Mon, 7 Sep 2020 00:35:50 +0200 Subject: New blog post --- content/2020-09-06-esp-and-micropython.md | 203 ++++++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 content/2020-09-06-esp-and-micropython.md (limited to 'content/2020-09-06-esp-and-micropython.md') diff --git a/content/2020-09-06-esp-and-micropython.md b/content/2020-09-06-esp-and-micropython.md new file mode 100644 index 0000000..b5002ce --- /dev/null +++ b/content/2020-09-06-esp-and-micropython.md @@ -0,0 +1,203 @@ +~ title: Getting started with MicroPython and ESP8266 +~ description: Getting started with MicroPython and ESP8266 +~ slug: /esp8266-and-micropython-guide.html +~ date: 2020-09-06 +~ template: post +~ hide: false + +**Table of contents** + +1. [Introduction](#introduction) +2. [Flashing the SOC](#flashing-the-soc) +3. [Install better tooling](#install-better-tooling) +4. [Additional resources](#additional-resources) + + +## Introduction + +A while ago I bought some [ESP8266](https://www.espressif.com/en/products/socs/esp8266) and [ESP32](https://www.espressif.com/en/products/socs/esp32) dev boards to play around with and I finally found a project to try it out. + +For my project, I used [ESP32](https://www.espressif.com/en/products/socs/esp32) but I could easily choose [ESP8266](https://www.espressif.com/en/products/socs/esp8266). This guide contains which tools I use and how I prepared my workspace to code for [ESP8266](https://www.espressif.com/en/products/socs/esp8266). + +![ESP8266 and ESP32 boards](/assets/esp8366-micropython/boards.jpg) + +This guide covers: +- flashing SOC +- install proper tooling +- deploying a simple script + +> Make sure that you are using **a good USB cable**. I had some problems with mine and once I replaced it everything started to work. + +## Flashing the SOC + +Plug your ESP8266 to USB port and check if the device was recognized with executing `dmesg | grep ch341-uart`. + +Then check if the device is available under `/dev/` by running `ls /dev/ttyUSB*`. + +> **Linux users**: if a device is not available be sure you are in `dialout` group. You can check this by executing `groups $USER`. You can add a user to `dialout` group with `sudo adduser $USER dialout`. + +After these conditions are meet go to the navigate to [https://micropython.org/download/esp8266/](https://micropython.org/download/esp8266/) and download `esp8266-20200902-v1.13.bin`. + +```sh +mkdir esp8266-test +cd esp8266-test + +wget https://micropython.org/resources/firmware/esp8266-20200902-v1.13.bin +``` + +After obtaining firmware we will need some tooling to flash the firmware to the board. + +```sh +sudo pip3 install esptool +``` + +You can read more about `esptool` at [https://github.com/espressif/esptool/](https://github.com/espressif/esptool/). + +Before flashing the firmware we need to erase the flash on device. Substitute `USB0` with the device listed in output of `ls /dev/ttyUSB*`. + +```sh +esptool.py --port /dev/ttyUSB0 erase_flash +``` + +If flash was successfully erased it is now time to flash the new firmware to it. + +```sh +esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 esp8266-20200902-v1.13.bin +``` + +If everything went ok you can try accessing MicroPython REPL with `screen /dev/ttyUSB0 115200` or `picocom /dev/ttyUSB0 -b115200`. + +> Sometimes you will need to press `ENTER` in `screen` or `picocom` to access REPL. + +When you are in REPL you can test if all is working properly following steps. + +```py +> import machine +> machine.freq() +``` + +This should output a number representing a frequency of the CPU (mine was `80000000`). + +When you are in `screen` or `picocom` these can help you a bit. + +| Key | Command | +| -------- | -------------------- | +| CTRL+d | preforms soft reboot | +| CTRL+a x | exits picocom | +| CTRL+a \ | exits screen | + + +## Install better tooling + +Now, to make our lives a little bit easier there are couple of additional tools that will make this whole experience a little more bearable. + +There are twq cool ways of uploading local files to SOC flash. + +- ampy → [https://github.com/scientifichackers/ampy](https://github.com/scientifichackers/ampy) +- rshell → [https://github.com/dhylands/rshell](https://github.com/dhylands/rshell) + +### ampy + +```bash +# installing ampy +sudo pip3 install adafruit-ampy +``` + +Listed below are some common commands I used. + +```bash + +# uploads file to flash +ampy --delay 2 --port /dev/ttyUSB0 put boot.py + +# lists file on flash +ampy --delay 2 --port /dev/ttyUSB0 ls + +# outputs contents of file on flash +ampy --delay 2 --port /dev/ttyUSB0 cat boot.py +``` + +> I added `delay` of 2 seconds because I had problems with executing commands. + +### rshell + +Even though `ampy` is a cool tool I opted with `rshell` in the end since it's much more polished and feature rich. + +```bash +# installing ampy +sudo pip3 install rshell +``` + +Now that `rshell` is installed we can connect to the board. + +```bash +rshell --buffer-size=30 -p /dev/ttyUSB0 -a +``` + +This will open a shell inside bash and from here you can execute multiple commands. You can check what is supported with `help` once you are inside of a shell. + +```bash +m@turing ~/Junk/esp8266-test +$ rshell --buffer-size=30 -p /dev/ttyUSB0 -a + +Using buffer-size of 30 +Connecting to /dev/ttyUSB0 (buffer-size 30)... +Trying to connect to REPL connected +Testing if ubinascii.unhexlify exists ... Y +Retrieving root directories ... /boot.py/ +Setting time ... Sep 06, 2020 23:54:28 +Evaluating board_name ... pyboard +Retrieving time epoch ... Jan 01, 2000 +Welcome to rshell. Use Control-D (or the exit command) to exit rshell. +/home/m/Junk/esp8266-test> help + +Documented commands (type help ): +======================================== +args cat connect date edit filesize help mkdir rm shell +boards cd cp echo exit filetype ls repl rsync + +Use Control-D (or the exit command) to exit rshell. +``` + +> Inside a shell `ls` will display list of files on your machine. To get list of files on flash folder `/pyboard` is remapped inside the shell. To list files on flash you must perform `ls /pyboard`. + +#### Moving files to flash + +To avoid copying files all the time I used `rsync` function from the inside of `rshell`. + +```bash +rsync . /pyboard +``` + +#### Executing scripts + +It is a pain to continuously reboot the device to trigger `/pyboard/boot.py` and there is a better way of testing local scripts on remote device. + +Lets assume we have `src/freq.py` file that displays CPU frequency of a remote device. + +```py +# src/freq.py + +import machine +print(machine.freq()) +``` + +Now lets upload this and execute it. + +```bash +# syncs files to remove device +rsync ./src /pyboard + +# goes into REPL +repl + +# we import file by importing it without .py extension and this will run the script +> import freq + +# CTRL+x will exit REPL +``` + +## Additional resources + +- [https://randomnerdtutorials.com/getting-started-micropython-esp32-esp8266/](https://randomnerdtutorials.com/getting-started-micropython-esp32-esp8266/) +- [http://docs.micropython.org/en/latest/esp8266/quickref.html](http://docs.micropython.org/en/latest/esp8266/quickref.html) -- cgit v1.2.3