MicroPython Basics Cheat Sheet

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1. What is MicroPython?

• MicroPython is a compact version of Python 3 optimized to run on microcontrollers.
• Boards Supported:
  • ESP8266 / ESP32
  • Raspberry Pi Pico
  • PyBoard
  • STM32, RP2040, etc.

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2. Installation (Microcontroller Setup)

Flash MicroPython Firmware (ESP32/ESP8266):

1. Download Firmware:
   https://micropython.org/download/
2. Install esptool:

   pip install esptool
   

3. Erase Flash:

   esptool.py --port /dev/ttyUSB0 erase_flash  
   

4. Flash Firmware:

   esptool.py --port /dev/ttyUSB0 write_flash -z 0x1000 firmware.bin  
   

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3. Connecting to MicroPython

REPL (Read Evaluate Print Loop):

screen /dev/ttyUSB0 115200  # Linux/Mac  
putty (COM port)            # Windows  

• Exit REPL: Ctrl + A + K (or unplug/reset)

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4. Basic MicroPython Workflow

1. Connect to Board via USB.
2. Flash Firmware.
3. Use REPL for Testing.
4. Upload Scripts (via rshell/ampy).

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5. Writing and Uploading Code

1. Create Python File (main.py):

print("Hello, MicroPython!")

2. Upload to Board:

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

3. Run Code on Boot (Place in main.py or boot.py).

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6. GPIO (Pin Control)

from machine import Pin  
led = Pin(2, Pin.OUT)  # GPIO2 (ESP32)  
led.value(1)           # Turn LED On  
led.value(0)           # Turn LED Off  

Button Input:

button = Pin(12, Pin.IN, Pin.PULL_UP)  # Pull-up resistor  
if button.value() == 0:  
    print("Button Pressed")  

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7. Blinking LED (Basic Project)

from machine import Pin  
import time  

led = Pin(2, Pin.OUT)  # GPIO2 (Built-in LED on ESP32)  

while True:  
    led.value(1)  
    time.sleep(1)  
    led.value(0)  
    time.sleep(1)  

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8. PWM (Pulse Width Modulation)

from machine import Pin, PWM  
led = PWM(Pin(2), freq=500, duty=512)  # 50% duty cycle  
led.duty(1023)  # Full brightness  
led.duty(0)     # Off  

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9. Analog to Digital Conversion (ADC)

from machine import ADC, Pin  
adc = ADC(Pin(36))  # GPIO36 (ADC1)  
adc.atten(ADC.ATTN_11DB)  # Max voltage 3.6V  
value = adc.read()  
print(value)  

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10. I2C (Sensor Communication)

from machine import Pin, I2C  

i2c = I2C(0, scl=Pin(22), sda=Pin(21))  # ESP32 Pins  
devices = i2c.scan()  
print(devices)  # List of detected devices  

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11. SPI (Serial Peripheral Interface)

from machine import SPI, Pin  

spi = SPI(1, baudrate=1000000, polarity=0, phase=0, sck=Pin(18), mosi=Pin(23), miso=Pin(19))  

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12. UART (Serial Communication)

from machine import UART  
uart = UART(1, baudrate=9600, tx=17, rx=16)  
uart.write("Hello")  
response = uart.read()  
print(response)  

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13. Reading Sensors (DHT11 Example)

import dht  
from machine import Pin  

sensor = dht.DHT11(Pin(4))  # GPIO4  
sensor.measure()  
print("Temp:", sensor.temperature())  
print("Humidity:", sensor.humidity())  

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14. Network (WiFi Connection ESP32/ESP8266)

import network  

wifi = network.WLAN(network.STA_IF)  
wifi.active(True)  
wifi.connect("YourSSID", "YourPassword")  

while not wifi.isconnected():  
    pass  

print("Connected, IP:", wifi.ifconfig())  

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15. Web Server (ESP32/ESP8266)

import socket  
import network  

wifi = network.WLAN(network.STA_IF)  
wifi.active(True)  
wifi.connect("YourSSID", "YourPassword")  

while not wifi.isconnected():  
    pass  

s = socket.socket()  
s.bind(('', 80))  
s.listen(5)  

while True:  
    conn, addr = s.accept()  
    conn.send("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\nHello, World!")  
    conn.close()  

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16. File System Commands (REPL)

import os  
os.listdir()               # List files  
os.remove('main.py')       # Delete file  
f = open('test.txt', 'w')  # Create file  
f.write('Hello')  
f.close()  

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17. Power Saving (Deep Sleep)

from machine import deepsleep  
deepsleep(10000)  # Sleep for 10 seconds  

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18. Firmware Management

• Erase Flash:

  esptool.py erase_flash
  

• Reflash Firmware:

  esptool.py write_flash -z 0x1000 firmware.bin
  

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19. Upload Files to MicroPython

1. Install ampy:

   pip install adafruit-ampy
   

2. Upload Python File:

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

3. List Files:

   ampy --port /dev/ttyUSB0 ls  
   

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20. MicroPython Common Modules

• machine – Access GPIO, ADC, I2C, SPI, etc.
• network – Manage WiFi and networking.
• time – Handle delays and real-time clock.
• os – File system operations.
• dht – DHT11/DHT22 sensors.

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Example: Control LED via Web (ESP32/ESP8266)

import network
import socket
from machine import Pin

led = Pin(2, Pin.OUT)
wifi = network.WLAN(network.STA_IF)
wifi.active(True)
wifi.connect("YourSSID", "YourPassword")

while not wifi.isconnected():
    pass

s = socket.socket()
s.bind(('', 80))
s.listen(5)

while True:
    conn, addr = s.accept()
    request = conn.recv(1024)
    led.value(not led.value())  # Toggle LED
    conn.send("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\nLED Toggled!")
    conn.close()