rpi_lcd_i2c_micropython

A small MicroPython driver for HD44780-compatible character LCDs connected through a common PCF8574 I2C backpack.

This is a MicroPython library. Install it onto a MicroPython board's filesystem; installing it with desktop CPython pip on Linux does not make machine available.

Usage

from machine import I2C, Pin
from rpi_lcd_i2c_micropython import I2cLcd

i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)
print([hex(addr) for addr in i2c.scan()])

lcd = I2cLcd(i2c, 0x27, 2, 16)  # address, rows, columns
lcd.putstr("Hello, world!")
lcd.move_to(0, 1)
lcd.putstr("MicroPython")

Change the I2C bus, pins, address, row count, and column count for your board and LCD. Common backpack addresses are 0x27 and 0x3F; use i2c.scan() to check.

Install on a board

Copy the src/rpi_lcd_i2c_micropython/ package directory to the board's /lib/rpi_lcd_i2c_micropython/ directory using Thonny or mpremote. The package on PyPI is the source distribution for developers and tools; MicroPython boards do not generally run desktop pip directly.

Wiring caution

Use I2C signals that are safe for your board's logic voltage. Many LCD backpacks powered at 5 V pull SDA/SCL up to 5 V, which can damage 3.3 V boards. Use suitable level shifting or 3.3 V pull-ups.

Compatibility

This driver assumes the common PCF8574 backpack pin mapping. Some backpacks use a different mapping. Test on your target board before relying on it in a project.