(原) Golang控制SPI设备：用Goalng控制ReSpeaker的LED灯

之前的文章提到以前购买的ReSpeaker扩展板，用Python控制总觉得有点不爽，于是搜索Golang的实现方法。

另外还有一个库，没有仔细看：https://github.com/kidoman/embd
再就是GPIO控制 https://github.com/stianeikeland/go-rpio
这是本程序使用的库https://github.com/goiot/devices

以下代码实现了对SPI设备的控制。

import (
        "bytes"
        "encoding/binary"
        "github.com/goiot/devices/dotstar"
        "golang.org/x/exp/io/spi"
)

const n = 3 // LED数量，看起来它是可以控制一个灯带的

// 要将整形变为Byte型。这里只用了一位，所以作了修改。
func IntToBytes(n int) byte {
  x := int32(n)
  bytesBuffer := bytes.NewBuffer([]byte{})
  binary.Write(bytesBuffer, binary.BigEndian, x)
  return bytesBuffer.Bytes()[3]
}

func main() {
        d, err := dotstar.Open(&spi.Devfs{Dev: "/dev/spidev0.1", Mode: spi.Mode3}, n) // 这个/dev可以用ls查看
        if err != nil {
                panic(err)
        }

        for i := 0; i < n; i++ {
                d.SetRGBA(i, dotstar.RGBA{0, IntToBytes(i*30+100), 0, 100}) // 颜色控制
        }

        if err := d.Draw(); err != nil {
                panic(err)
        }
}

改个版，命令行控制三个LED

package main

import (
        "fmt"
        "flag"
        "bytes"
        "strconv"
        "encoding/binary"
        "github.com/goiot/devices/dotstar"
        "golang.org/x/exp/io/spi"
)

func Hex2Dec(val string) int {
        n, err := strconv.ParseUint(val, 16, 32)
        if err != nil {
                fmt.Println(err)
        }
        return int(n)
}

func IntToBytes(n int) byte {
  x := int32(n)
  bytesBuffer := bytes.NewBuffer([]byte{})
  binary.Write(bytesBuffer, binary.BigEndian, x)
  return bytesBuffer.Bytes()[3]
}

func ColorSplit(s string) (r,g,b,a byte){
  m := []rune(s)
  r = IntToBytes(Hex2Dec(string(m[0:2])))
  g = IntToBytes(Hex2Dec(string(m[2:4])))
  b = IntToBytes(Hex2Dec(string(m[4:6])))
  a = IntToBytes(Hex2Dec(string(m[6:8])))
  return
}

func main() {
        var Led0,Led1,Led2 string

        flag.StringVar(&Led0,"l1","00000000","1灯值: RRGGBBAA(AA=01-1F)")
        flag.StringVar(&Led1,"l2","00000000","2灯值：RRGGBBAA(AA=01-1F)")
        flag.StringVar(&Led2,"l3","00000000","3灯值：RRGGBBAA(AA=01-1F)")
        flag.Parse()

        d, err := dotstar.Open(&spi.Devfs{Dev: "/dev/spidev0.1", Mode: spi.Mode3}, 3)
        if err != nil {
                panic(err)
        }
        r0,g0,b0,a0:= ColorSplit(Led0)
        d.SetRGBA(0, dotstar.RGBA{r0, g0, b0, a0})
        r1,g1,b1,a1:= ColorSplit(Led1)
        d.SetRGBA(1, dotstar.RGBA{r1, g1, b1, a1})
        r2,g2,b2,a2:= ColorSplit(Led2)
        d.SetRGBA(2, dotstar.RGBA{r2, g2, b2, a2})
        d.Draw()
}