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

package main

import (
  "time"
  "machine"

  "github.com/antonfisher/is31fl3731"
)

// 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)
    return
  }

  // Create driver for Adafruit 15x7 CharliePlex LED Matrix FeatherWing
  // (CharlieWing): https://www.adafruit.com/product/3163
  ledMatrix, err := is31fl3731.NewAdafruitCharlieWing15x7(bus, I2CAddress)
  if err != nil {
    println("could not create driver:", err)
    return
  }

  // 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...")
    ledMatrix.SetActiveFrame(is31fl3731.FRAME_0)
    time.Sleep(time.Second * 3)

    println("show frame #1...")
    ledMatrix.SetActiveFrame(is31fl3731.FRAME_1)
    time.Sleep(time.Second * 3)
  }
}