From d2dea8058c88b39f161178f59c6bfec0e32dfa02 Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@martin-laptop.lan>
Date: Fri, 18 May 2018 22:22:20 +0100
Subject: Initial implementation of go unicorn hat driver

---
 RealUnicorn.go | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 RealUnicorn.go

(limited to 'RealUnicorn.go')

diff --git a/RealUnicorn.go b/RealUnicorn.go
new file mode 100644
index 0000000..d9665d8
--- /dev/null
+++ b/RealUnicorn.go
@@ -0,0 +1,62 @@
+package main
+
+import (
+	"golang.org/x/exp/io/spi"
+	"log"
+)
+
+type RealUnicorn struct {
+	BaseUnicorn
+	device *spi.Device
+}
+
+// NewReal ...
+// Constructs a new real unicorn from fairy dust and sprinkles
+func NewReal() (*RealUnicorn, error) {
+	dev, err := spi.Open(&spi.Devfs{
+		Dev:      "/dev/spidev0.0",
+		Mode:     spi.Mode0,
+		MaxSpeed: 9000000,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return &RealUnicorn{
+		BaseUnicorn{
+			pixels: makePixels(16, 16),
+		},
+		dev,
+	}, nil
+}
+
+func (u *RealUnicorn) Show() {
+	// Width * height * colours + leading bit
+	width := u.GetWidth()
+	height := u.GetHeight()
+	write := make([]byte, (width*height*3)+1)
+
+	// Add the leading bit
+	write[0] = 0x72
+	// Add all the pixel values
+	ix := 1
+	for x := uint8(0); x < width; x++ {
+		for y := uint8(0); y < height; y++ {
+			for j := 0; j < 3; j++ {
+				write[ix] = u.pixels[x][y][j]
+				ix++
+			}
+		}
+	}
+	// Write to the device
+	err := u.device.Tx(write, nil)
+	if err != nil {
+		log.Printf("Error writing to SPI device %v", err)
+	}
+}
+func (u *RealUnicorn) Off() {
+	u.Close()
+}
+func (u *RealUnicorn) Close() error {
+	return u.device.Close()
+}
-- 
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