MicroPython on ESP32/ESP8266 microcontollers

• Installation
• Usage
• Exercises
• List of MicroPython examples
• Components and tools
• References

The repository contains MicroPython lab exercises for Digital Electronics course at Brno University of Technology, Czechia. The course focuses on digital circuits, microprocessor technology, embedded systems and uses the MicroPython language for programming 32-bit microcontrollers. Students will gain practical experience with individual parts of microprocessor systems and will also expand their knowledge of Python programming language.

Installation

To use MicroPython with a real ESP32 board, you will need to follow these steps:

• Download MicroPython firmware
• Flash the firmware
• Connect to the Board's Serial REPL and interact with MicroPython
• Transfer files to the ESP32 board

There are several very good tutorials how to install and use MicroPython on an ESP microcontroller, such as this one for Windows. The following text was tested under Linux-based operating system.

NOTE: The MicroPython firmware can also be flashed by Thonny IDE.

1. Install Python.

2. Open terminal (typically Ctrl+Alt+T) and install esptool:

   pip install esptool

   Connect your ESP board and test the esptool:

   # Get the version
   esptool.py version
   
   # Read chip info, serial port, MAC address, and others
   # Note: Use `dmesg` command to find your USB port
   esptool.py --port /dev/ttyUSB0 flash_id
   
   # Read all eFuses from the chip
   espefuse.py --port /dev/ttyUSB0 summary

For ESP32 chips:

3. Download the latest firmware for your target device, such as esp32-20230426-v1.20.0.bin for Espressif ESP32.

4. Erase the Flash of target device (use your port name):

   esptool.py --chip esp32 --port /dev/ttyUSB0 erase_flash

5. Deploy the new firmware:

   esptool.py --chip esp32 --port /dev/ttyUSB0 write_flash -z 0x1000 esp32-20230426-v1.20.0.bin

For ESP8266 chips:

3. Download the latest firmware, such as esp8266-20230426-v1.20.0.bin.

4. Erase the Flash before deploying the firmware:

   esptool.py --chip esp8266 --port /dev/ttyUSB0 erase_flash

5. Deploy the firmware:

   esptool.py --chip esp8266 --port /dev/ttyUSB0 write_flash --flash_mode dio --flash_size 4MB 0x0 esp8266-20230426-v1.20.0.bin

Usage

Test MicroPython via PuTTY or directly in terminal by screen. You need to press on-board reset button:

screen /dev/ttyUSB0 115200

Note: To exit the screen, press Ctrl+A, followed by K and Y.

# Print string to a Shell
>>> print("Hi there!")
Hi there!

# Operators used for the different functions like division,
# multiplication, addition, subtraction, ...
>>> 10/3
3.333333
>>> 10//3
3
>>> 10%3
1
>>> 10*3
30
>>> 10**3
1000

# Integers, floats, strings
>>> type(10)
<class 'int'>
>>> type(10.0)
<class 'float'>

>>> pi = 3.1415
>>> pi_str = str(pi)
>>> type(pi_str)
<class 'str'>
>>> len(pi_str)
6

# `ord` returns unicode code of a specified character
>>> ord("A")
65
>>> ord("a")
97
>>> ord("0")
48

>>> print(pi_str)
3.1415
>>> ord(pi_str[0])
51
>>> ord(pi_str[-1])
53

See MicroPython tutorials, such as MicroPython Programming Basics with ESP32 and ESP8266 for detailed explanation.

Test some other useful commands from Quick reference for the ESP32:

# A platform identifier
>>> import sys
>>> sys.platform
'esp32'

# Get the current frequency of the CPU and RTC time
>>> import machine
>>> help(machine)
>>> machine.freq()
>>> machine.RTC().datetime()

# Get Flash size in Bytes
>>> import esp
>>> esp.flash_size()

# Read the internal temperature (in Fahrenheit)
>>> import esp32
>>> esp32.raw_temperature()
# FYI: temp_c = (temp_f-32) * (5/9)
#      temp_f = temp_c * (9/5) + 32

Exercises

1. Tools for programming and debugging ESP32 microcontrollers
2. Programming in Python, Git version-control system
3. Control of GPIO pins
4. Timers
5. LCD (Liquid Crystal Display)
6. I2C serial communication
7. Wi-Fi communication
8. Project

List of MicroPython examples

• Blink
• Timer blink
• Wi-Fi scan
• Wi-Fi connection
• I2C humidity & temperature sensor
• I2C sensor & ThingSpeak
• RTC & NTP times
• Wi-Fi access point
• Web server & I2C sensor
• Jupyter example

Components and tools

The following hardware and software components are mainly used in the lab.

Component	Link(s)
ESP32 microcontroler	Expressif
FireBeetle board	Schematic & manual, pinout
DHT12	I2C humidity and temperature sensor: data sheet
MPU6050	I2C gyroscope and accelerometer: data sheet
DS3231	I2C real time clock: data sheet
HC-SR04	ultrasonic sensor: datasheet
Joystick PS2	Analog joystick PS2
Logic analyzer	24MHz 8-channel logic analyzer: software
Osciloscope DSOX3034T	Oscilloscope Keysight Technologies DSOX3034T (350 MHz, 4 analog channels), including 16 logic timing channels DSOXT3MSO and serial protocol triggering and decode options D3000BDLA
Thonny IDE	Python IDE for beginners
Mu editor	Python editor
Visual Studio Code	web page
Git	git

Tested on

Version	Result (yyyy-mm-dd)	Note
Windows 10	OK (2023-09-18)	Lab SC 6.61
Linux Mint 20.3 (Una)	OK (2023-05-23)	Laptop

# FYI: How to check OS version in Linux
cat /etc/os-release

# Or by Neofetch
neofetch

References

1. Peter Kazarinoff. How to install MicroPython on an ESP32 microcontroller

2. IDEs for MicroPython

3. ESP32 brief overview (YouTube video)

4. Getting started with MicroPython on the ESP32

5. Video tutorial about ESP32 MicroPython

6. MicroPython Documentation. Quick reference for the ESP32

7. DFRobot. 250+ Must-read Tutorials for Learning ESP32 and Arduino

8. 40+ MicroPython Projects, Tutorial and Guides with ESP32 / ESP8266

9. Rafael Aroca. ESP32, Camera, MicroPython and NO esptool!