Waveshare E-Paper 2.9inch Driver in Golang

epd2in9.go

package main

import (
	"github.com/stianeikeland/go-rpio/v4"
	"log"
	"time"
)

const (
	RST    = rpio.Pin(17)
	DC     = rpio.Pin(25)
	CS     = rpio.Pin(8)
	BUSY   = rpio.Pin(24)
	HEIGHT = 296
	WIDTH  = 128
)

type LUT []byte

var lut_full_update = LUT{
	0x50, 0xAA, 0x55, 0xAA, 0x11, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0xFF, 0xFF, 0x1F, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}

//noinspection GoUnusedGlobalVariable
var lut_partial_update = LUT{
	0x10, 0x18, 0x18, 0x08, 0x18, 0x18,
	0x08, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x13, 0x14, 0x44, 0x12,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}

func reset() {
	RST.Write(rpio.High)
	time.Sleep(200 * time.Millisecond)
	RST.Write(rpio.Low)
	time.Sleep(10 * time.Millisecond)
	RST.Write(rpio.High)
	time.Sleep(200 * time.Millisecond)
}

func command(c byte) {
	DC.Write(rpio.Low)
	CS.Write(rpio.Low)
	rpio.SpiTransmit(c)
	CS.Write(rpio.High)
}

func data(d byte) {
	DC.Write(rpio.High)
	CS.Write(rpio.Low)
	rpio.SpiTransmit(d)
	CS.Write(rpio.High)
}

func idle() {
	for BUSY.Read() == rpio.High {
		time.Sleep(200 * time.Millisecond)
	}
}

func initialize(lut LUT) {
	reset()

	// DRIVER_OUTPUT_CONTROL
	command(0x01)
	data((HEIGHT - 1) & 0xFF)
	data(((HEIGHT - 1) >> 8) & 0xFF)
	data(0x00)

	// BOOSTER_SOFT_START_CONTROL
	command(0x0C)
	data(0xD7)
	data(0xD6)
	data(0x9D)

	// WRITE_VCOM_REGISTER
	command(0x2C)
	data(0xA8)

	// SET_DUMMY_LINE_PERIOD
	command(0x3A)
	data(0x1A)

	// SET_GATE_TIME
	command(0x3B)
	data(0x08)

	// DATA_ENTRY_MODE_SETTING
	command(0x11)
	data(0x03)

	// WRITE_LUT_REGISTER
	command(0x32)
	for _, b := range lut {
		data(b)
	}
}

func sleep() {
	command(0x10)
	data(0x01)
}

func turnOnDisplay() {
	command(0x22)
	data(0xC4)
	command(0x20)
	command(0xFF)
	idle()
}

func window(x0, x1 byte, y0, y1 uint16) {
	command(0x44)
	data((x0 >> 3) & 0xFF)
	data((x1 >> 3) & 0xFF)

	command(0x45)
	data(byte(y0 & 0xFF))
	data(byte((y0 >> 8) & 0xFF))
	data(byte(y1 & 0xFF))
	data(byte((y1 >> 8) & 0xFF))
}

func cursor(x uint8, y uint16) {
	command(0x4E)
	data((x >> 3) & 0xFF)

	command(0x4F)
	data(byte(y & 0xFF))
	data(byte((y >> 8) & 0xFF))

	idle()
}

func clear(color byte) {
	window(0, WIDTH-1,0, HEIGHT-1)
	for i := 0; i < HEIGHT; i++ {
		cursor(0, uint16(i))
		command(0x24)
		for j := 0; j < (WIDTH / 8); j++ {
			data(color)
		}
	}
	turnOnDisplay()
}

func draw(image []byte) {
	window(0, WIDTH-1, 0, HEIGHT-1)
	for i := 0; i < HEIGHT; i++ {
		cursor(0, uint16(i))
		for j := 0; j < (WIDTH / 8); j++ {
			data(image[i+j*(WIDTH/8)])
		}
	}
}

func main() {
	// start the GPIO controller
	if err := rpio.Open(); err != nil {
		log.Fatalf("failed to start gpio: %v", err)
	}
	defer rpio.Close()

	// Enable SPI on SPI0
	if err := rpio.SpiBegin(rpio.Spi0); err != nil {
		log.Fatalf("failed to enable SPI: %v", err)
	}

	// set pin modes
	RST.Mode(rpio.Output)
	DC.Mode(rpio.Output)
	CS.Mode(rpio.Output)
	BUSY.Mode(rpio.Input)

	// configure SPI settings
	rpio.SpiSpeed(4_000_000)
	rpio.SpiMode(0, 0)

	// initialize the display
	initialize(lut_full_update)
	clear(0xFF)
	sleep()
}