software: communication: Use Go channels

Go channels help to decouple the communication layers defined by the OSI
model [1]. The physical layer can be abstracted by an RX and TX byte
channel and the data link layer by two frame channels.

[1]: https://en.wikipedia.org/wiki/OSI_model

1 files changed, 45 insertions, 0 deletions

diff --git a/software/communication/physical.go b/software/communication/physical.go
index 853e4c4..0ba3690 100644
--- a/software/communication/physical.go
+++ b/software/communication/physical.go
@@ -1,6 +1,9 @@
 package communication
 
 import (
+	"fmt"
+	"log"
+
 	"go.bug.st/serial"
 	"go.bug.st/serial/enumerator"
 )
@@ -9,6 +12,35 @@ const (
 	ST_VID = `0483`
 )
 
+type physical struct {
+	port serial.Port
+	rx   chan byte
+}
+
+func newPhysical() (physical, error) {
+	p := physical{}
+
+	devices, err := getStSerials()
+	if err != nil {
+		return p, err
+	}
+
+	if len(devices) != 1 {
+		return p, fmt.Errorf("Require exactly one serial device from STMicroelectronics but %d attached", len(devices))
+	}
+	device := devices[0]
+
+	p.port, err = openSerial(device)
+	if err != nil {
+		return p, err
+	}
+
+	p.rx = make(chan byte)
+	go p.Receive()
+
+	return p, nil
+}
+
 func getStSerials() ([]string, error) {
 	retval := make([]string, 0)
 
@@ -39,3 +71,16 @@ func openSerial(device string) (serial.Port, error) {
 	}
 	return port, nil
 }
+
+func (p *physical) Receive() {
+	for {
+		buff := make([]byte, 100)
+		n, err := p.port.Read(buff)
+		if err != nil {
+			log.Fatal(err)
+		}
+		for i := 0; i < n; i++ {
+			p.rx <- buff[i]
+		}
+	}
+}