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// +build linux,arm linux,arm64
package unicorn
import (
"github.com/ecc1/spi"
"log"
"os"
"syscall"
)
type RealUnicorn struct {
BaseUnicorn
device *spi.Device
}
// NewUnicorn ...
// Constructs a new real unicorn from fairy dust and sprinkles
func NewUnicorn() (*RealUnicorn, error) {
dev, err := spi.Open("/dev/spidev0.0", 9000000, 0)
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 := int(u.GetWidth())
height := int(u.GetHeight())
sz := (width * height * 3) + 1
write := make([]byte, sz)
// Add the leading bit
write[0] = 0x72
// Add all the pixel values
ix := 1
for x := 0; x < width; x++ {
for y := 0; y < height; y++ {
for j := 0; j < 3; j++ {
write[ix] = byte(u.pixels[x][y][j])
ix++
}
}
}
// Write to the device
err := u.device.Transfer(write)
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()
}
// MainLoop ...
// Do nothing until SIGTERM, then close the SPI library
func (u *RealUnicorn) MainLoop() {
c := make(chan os.Signal, 2)
signal.Notify(c, os.Interrupt, syscall.SIGTERM)
<-c
u.Close()
}
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