main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"os/signal"
	"sync"
	"time"

	"github.com/kidoman/embd"
	_ "github.com/kidoman/embd/host/rpi"

	"github.com/carloop/simulator-program/mcp2515"
)

func main() {
	flag.Parse()

	err := embd.InitSPI()
	if err != nil {
		panic(err)
	}
	defer embd.CloseSPI()

	const (
		device  = 0
		speed   = 1e5
		bpw     = 8
		delay   = 0
		channel = 0
	)

	spi := embd.NewSPIBus(embd.SPIMode0, device, int(speed), bpw, delay)
	defer spi.Close()

	canDevice := mcp2515.New(spi)
	err = canDevice.Setup(500000)

	if err != nil {
		printError(err)
		return
	}

	rxChan := make(mcp2515.MsgChan, 10)
	txChan := make(mcp2515.MsgChan, 10)
	errChan := make(mcp2515.ErrChan, 10)

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.Done()
		mcp2515.RunMessageLoop(canDevice, rxChan, txChan, errChan)
	}()
	wg.Add(1)
	go func() {
		defer wg.Done()
		printCanMessages(rxChan, txChan, errChan)
	}()
	wg.Add(1)
	go func() {
		defer wg.Done()
		sendMessages(txChan)
	}()

	// Wait for all goroutines to be done
	wg.Wait()
}

func printCanMessages(rxChan mcp2515.MsgChan, txChan mcp2515.MsgChan,
	errChan mcp2515.ErrChan) {

	fmt.Println("Starting CAN receiver")

	startTime := time.Now()

	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)

	for {
		select {
		case rxMessage := <-rxChan:
			printMessage(rxMessage, startTime)
		case err := <-errChan:
			printError(err)
		case <-c:
			// Program done
			return
		}
	}
}

func printMessage(message *mcp2515.Message, startTime time.Time) {
	timeOffset := message.Time.Sub(startTime).Seconds()
	fmt.Printf("%15.6f %03x %d", timeOffset, message.Id, message.Length)
	for i := uint8(0); i < message.Length; i++ {
		fmt.Printf(" %02x", message.Data[i])
	}
	fmt.Println("")

}

func printError(err error) {
	fmt.Printf("Error occured: %v", err)
	fmt.Println("")
}

func sendMessages(txChan mcp2515.MsgChan) {
	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)

	i := uint8(0)
	for {
		var message mcp2515.Message
		message.Id = 0x2AA
		message.Length = 8
		for j := 0; j < 8; j++ {
			message.Data[j] = 0xAA
		}
		i += 1

		select {
		case txChan <- &message:
			// Message added to queue

		case <-c:
			// Program done
			return
		default:
			// If tx channel is full, ignore
		}

		time.Sleep(10 * time.Millisecond)

	}
}