Added example to use 12 bit veriant

Signed-off-by: npotts <npotts@users.noreply.github.com>

samples/mcp3208.go

@@ -0,0 +1,48 @@
+// +build ignore
+
+// this sample uses the mcp3008 package to interface with a similar MCP3208, which is a 12 bit variant. Works without code change on bbb and rpi
+package main
+
+import (
+	"flag"
+	"fmt"
+	"time"
+
+	"github.com/kidoman/embd"
+	// "github.com/kidoman/embd/convertors/mcp3008"
+	_ "github.com/kidoman/embd/host/all"
+	"github.com/npotts/embd/convertors/mcp3008"
+)
+
+const (
+	channel = 0
+	speed   = 1000000
+	bpw     = 8
+	delay   = 0
+)
+
+func main() {
+	flag.Parse()
+	fmt.Println("this is a sample code for mcp3008 10bit 8 channel ADC")
+
+	if err := embd.InitSPI(); err != nil {
+		panic(err)
+	}
+	defer embd.CloseSPI()
+
+	spiBus := embd.NewSPIBus(embd.SPIMode0, channel, speed, bpw, delay)
+	defer spiBus.Close()
+
+	adc := &mcp3008.MCP3008{Mode: mcp3008.SingleMode, Bus: spiBus, Bits: mcp3008.Bits12}
+
+	// adc := mcp3008.New(mcp3008.SingleMode, spiBus)
+
+	for i := 0; i < 20; i++ {
+		time.Sleep(1 * time.Second)
+		val, err := adc.AnalogValueAt(0)
+		if err != nil {
+			panic(err)
+		}
+		fmt.Printf("analog value is: %v\n", val)
+	}
+}