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Go/TinyGo driver for Lumissil IS31FL3731 matrix LED driver.

PR to include this driver to the official TinyGo driver list

What’s implemented

  • picture mode (“auto frame play mode” and “audio frame play mode” are not
    supported in this version of the driver)
  • drawing by XY coordinates or raw pixel’s index on LED layout
  • frames (0-7) and switching between them

Supported boards

Chip details


Driver can work with any Go program that provides I2C interface like this:

type I2C interface {
  WriteRegister(addr uint8, r uint8, buf []byte) error

This is TinyGo example that uses
machine package’s I2C to control Adafruit 15×7 CharlieWing:

package main

import (


// I2CAddress -- address of led matrix
var I2CAddress uint8 = 0x74

func main() {
  bus := machine.I2C0
  err := bus.Configure(machine.I2CConfig{})
  if err != nil {
    println("could not configure I2C:", err)

  // Create driver for Adafruit 15x7 CharliePlex LED Matrix FeatherWing
  // (CharlieWing):
  ledMatrix, err := is31fl3731.NewAdafruitCharlieWing15x7(bus, I2CAddress)
  if err != nil {
    println("could not create driver:", err)

  // Fill the whole matrix on the frame #0 (visible by default)
  ledMatrix.Fill(is31fl3731.FRAME_0, uint8(3))

  // Draw couple pixels on the frame #1 (not visible yet)
  ledMatrix.DrawPixelXY(is31fl3731.FRAME_1, uint8(0), uint8(0), uint8(10))
  ledMatrix.DrawPixelXY(is31fl3731.FRAME_1, uint8(14), uint8(6), uint8(10))

  // There are 8 frames available, it's a good idea to draw on an invisible
  // frame and then switch to that frame to reduce flickering. Switch between
  // frame #0 and #1 in a loop to show animation:
  for {
    println("show frame #0...")
    time.Sleep(time.Second * 3)

    println("show frame #1...")
    time.Sleep(time.Second * 3)

This example code switches display between these two states:

picture of the display with all LEDs enabled
picture of the display with only two LEDs enabled

Note: tested on nRF52840 controller.

Inspired by

This driver inspired by Adafruit Python driver:


MIT License


View Github