display-epaper/epd/epd.go

296 lines
5.6 KiB
Go

package epd
import (
"fmt"
"image"
"log"
"periph.io/x/conn/v3/gpio"
"periph.io/x/conn/v3/physic"
"periph.io/x/conn/v3/spi"
"periph.io/x/conn/v3/spi/spireg"
"periph.io/x/host/v3/bcm283x"
"time"
)
const (
Width = 800
Height = 480
)
type EPD struct {
width int
height int
resetPin gpio.PinOut
dcPin gpio.PinOut
busyPin gpio.PinIn
csPin gpio.PinOut
pwrPin gpio.PinOut
partFlag byte
spi spi.Conn
spiReg spi.PortCloser
}
func New() (*EPD, error) {
epd := &EPD{
width: Width,
height: Height,
resetPin: bcm283x.GPIO17,
dcPin: bcm283x.GPIO25,
busyPin: bcm283x.GPIO24,
csPin: bcm283x.GPIO8,
pwrPin: bcm283x.GPIO18,
partFlag: 1,
}
return epd, nil
}
func (e *EPD) reset() {
e.resetPin.Out(gpio.High)
time.Sleep(20 * time.Millisecond)
e.resetPin.Out(gpio.Low)
time.Sleep(2 * time.Millisecond)
e.resetPin.Out(gpio.High)
time.Sleep(20 * time.Millisecond)
}
func (e *EPD) sendCommand(cmd byte) {
e.dcPin.Out(gpio.Low)
e.csPin.Out(gpio.Low)
if _, err := e.spiWrite([]byte{cmd}); err != nil {
log.Fatalf("writing to spi: %v", err)
}
e.csPin.Out(gpio.High)
}
func (e *EPD) sendData(data byte) {
e.dcPin.Out(gpio.High)
e.csPin.Out(gpio.Low)
if _, err := e.spiWrite([]byte{data}); err != nil {
log.Fatalf("writing to spi: %v", err)
}
e.csPin.Out(gpio.High)
}
func (e *EPD) sendDataSlice(data []byte) {
e.dcPin.Out(gpio.High)
toSend := len(data)
const maxSize = 4096
if toSend <= maxSize {
e.csPin.Out(gpio.Low)
if _, err := e.spiWrite(data); err != nil {
log.Fatalf("writing to spi: %v", err)
}
e.csPin.Out(gpio.High)
return
}
cursor := 0
for cursor < toSend {
chunk := data[cursor:min(cursor+maxSize, toSend)]
e.csPin.Out(gpio.Low)
if _, err := e.spiWrite(chunk); err != nil {
log.Fatalf("writing to spi: %v", err)
}
e.csPin.Out(gpio.High)
cursor = min(cursor+maxSize, toSend)
}
}
func (e *EPD) spiWrite(write []byte) ([]byte, error) {
read := make([]byte, len(write))
if err := e.spi.Tx(write, read); err != nil {
return nil, fmt.Errorf("tx: %w", err)
}
return read, nil
}
func (e *EPD) readBusy() {
e.sendCommand(0x71)
for e.busyPin.Read() == gpio.Low {
time.Sleep(20 * time.Millisecond)
e.sendCommand(0x71)
}
time.Sleep(20 * time.Millisecond)
}
func (e *EPD) turnOn() error {
log.Println("turning on")
if err := e.resetPin.Out(gpio.Low); err != nil {
return fmt.Errorf("setting reset pin to low: %w", err)
}
if err := e.dcPin.Out(gpio.Low); err != nil {
return fmt.Errorf("setting dc pin to low: %w", err)
}
if err := e.csPin.Out(gpio.Low); err != nil {
return fmt.Errorf("setting cs pin to low: %w", err)
}
if err := e.pwrPin.Out(gpio.High); err != nil {
return fmt.Errorf("setting pwr pin to low: %w", err)
}
var err error
if e.spiReg, err = spireg.Open("0"); err != nil {
return fmt.Errorf("opening SPI: %w", err)
}
c, err := e.spiReg.Connect(4*physic.MegaHertz, spi.Mode0, 8)
if err != nil {
return fmt.Errorf("connecting to SPI: %w", err)
}
e.spi = c
return nil
}
func (e *EPD) Init() error {
log.Println("initializing EPD")
if err := e.turnOn(); err != nil {
return fmt.Errorf("turning on: %w", err)
}
e.reset()
e.sendCommand(0x06)
e.sendDataSlice([]byte{0x17, 0x17, 0x28, 0x17})
e.sendCommand(0x01)
e.sendDataSlice([]byte{0x07, 0x07, 0x28, 0x17})
e.sendCommand(0x04)
time.Sleep(100 * time.Millisecond)
e.readBusy()
e.sendCommand(0x00)
e.sendData(0x1f)
e.sendCommand(0x61)
e.sendDataSlice([]byte{0x03, 0x20, 0x01, 0xe0})
e.sendCommand(0x15)
e.sendData(0x00)
e.sendCommand(0x50)
e.sendDataSlice([]byte{0x10, 0x07})
e.sendCommand(0x60)
e.sendData(0x22)
return nil
}
func (e *EPD) InitFast() error {
log.Println("initializing Fast EPD")
if err := e.turnOn(); err != nil {
return fmt.Errorf("turning on: %w", err)
}
e.reset()
e.sendCommand(0x00)
e.sendData(0x1f)
e.sendCommand(0x50)
e.sendDataSlice([]byte{0x10, 0x07})
e.sendCommand(0x04)
time.Sleep(100 * time.Millisecond)
e.readBusy()
e.sendCommand(0x06)
e.sendDataSlice([]byte{0x27, 0x27, 0x18, 0x17})
e.sendCommand(0xe0)
e.sendData(0x02)
e.sendCommand(0xe5)
e.sendData(0x5a)
return nil
}
func (e *EPD) Clear() {
log.Println("clearing epd")
e.Send(image.White)
}
func (e *EPD) Refresh() {
log.Println("refreshing...")
e.sendCommand(0x12)
time.Sleep(100 * time.Millisecond)
e.readBusy()
}
func (e *EPD) Sleep() error {
log.Println("sleeping display...")
e.sendCommand(0x02)
e.readBusy()
e.sendCommand(0x07)
e.sendData(0xa5)
time.Sleep(2 * time.Second)
if err := e.turnOff(); err != nil {
return fmt.Errorf("turning off: %w", err)
}
return nil
}
func (e *EPD) turnOff() error {
log.Println("turning off...")
if err := e.spiReg.Close(); err != nil {
return fmt.Errorf("closing SPI: %w", err)
}
e.resetPin.Out(gpio.Low)
e.dcPin.Out(gpio.Low)
e.pwrPin.Out(gpio.Low)
return nil
}
func (e *EPD) Send(img image.Image) {
if img == nil {
log.Println("empty img")
return
}
log.Println("sending img...")
toSend := make([]byte, 0, e.height*e.width/8)
toSend2 := make([]byte, 0, e.height*e.width/8)
for row := 0; row < e.height; row++ {
for col := 0; col < e.width; col += 8 {
// this loop converts individual pixels into a single byte
// 8-pixels at a time and then sends that byte to render
var b byte = 0xFF
for px := 0; px < 8; px++ {
var pixel = img.At(col+px, row)
if isdark(pixel.RGBA()) {
b &= ^(0x80 >> (px % 8))
}
}
toSend = append(toSend, ^b)
toSend2 = append(toSend2, b)
}
}
e.sendCommand(0x10)
e.sendDataSlice(toSend2)
e.sendCommand(0x13)
e.sendDataSlice(toSend)
}
func isdark(r, g, b, _ uint32) bool {
return r < 65535 || g < 65535 || b < 65535
}