Adding SSD1306 OLED display controller support

samples/ssd1306.go

@@ -0,0 +1,116 @@
+// +build ignore
+
+// This sample runs on a monochrome 128x64 OLED graphic display using an SSD1306 controller,
+// such as https://www.adafruit.com/product/938.
+// It demonstrates the rectangular fill/clear and point on/off operations animated across the display.
+
+package main
+
+import (
+	"github.com/golang/glog"
+	"github.com/kidoman/embd"
+	"github.com/kidoman/embd/controller/ssd1306"
+	_ "github.com/kidoman/embd/host/rpi" // This loads the RPi driver
+
+	"flag"
+	"os"
+	"os/signal"
+	"time"
+)
+
+func main() {
+	flag.Parse()
+	glog.Info("Starting")
+
+	if err := embd.InitSPI(); err != nil {
+		panic(err)
+	}
+	defer embd.CloseSPI()
+
+	spiBus := embd.NewSPIBus(embd.SPIMode0, 0, 1000000, 8, 0)
+	defer spiBus.Close()
+
+	if err := embd.InitGPIO(); err != nil {
+		panic(err)
+	}
+	defer embd.CloseGPIO()
+
+	dcPin := setupPin("GPIO_23")
+	defer dcPin.Close()
+	resetPin := setupPin("GPIO_24")
+	defer resetPin.Close()
+
+	controller, err := ssd1306.NewSPI(spiBus, dcPin, resetPin, 128, 64)
+	if err != nil {
+		glog.Fatalf("Failed to start: %s", err)
+	}
+	defer controller.Close()
+
+	buffer := controller.NewBuffer()
+	first := true
+	chunkWidth := 32
+	chunkHeight := 20
+	zipDir := 1
+	zipX := 0
+	prevZipX := 0
+	var prevX, prevY int
+
+	// Setup Control-C to gracefully stop
+	done := make(chan os.Signal, 1)
+	signal.Notify(done, os.Interrupt)
+
+outer:
+	for {
+
+		for y := 0; y+chunkHeight <= 64; y += chunkHeight {
+			for x := 0; x+chunkWidth <= 128; x += chunkWidth {
+				select {
+				case <-done:
+					break outer
+				default:
+					glog.Infof("x=%d, y=%d\n", x, y)
+					if !first {
+						buffer.ClearRect(prevX, prevY, chunkWidth, chunkHeight)
+					} else {
+						first = false
+					}
+					buffer.FillRect(x, y, chunkWidth, chunkHeight)
+					prevX = x
+					prevY = y
+
+					buffer.Off(prevZipX, 63)
+					buffer.On(zipX, 63)
+					prevZipX = zipX
+					zipX += zipDir
+					if zipX >= 128 {
+						zipX = 127
+						zipDir = -1
+					} else if zipX < 0 {
+						zipX = 0
+						zipDir = 1
+					}
+
+					controller.Display(buffer)
+
+					time.Sleep(100 * time.Millisecond)
+				}
+			}
+		}
+
+	}
+
+}
+
+func setupPin(key string) embd.DigitalPin {
+
+	p, err := embd.NewDigitalPin(key)
+	if err != nil {
+		panic(err)
+	}
+
+	if err := p.SetDirection(embd.Out); err != nil {
+		panic(err)
+	}
+
+	return p
+}