fix: default to Orange Pi UART0

cmd/groundstation/main.go

@@ -16,13 +16,13 @@ import (
 )
 
 func main() {
-	serialPath := flag.String("serial", "", "GX12 AUX1 UART device, e.g. /dev/ttyS1")
+	serialPath := flag.String("serial", "/dev/ttyS0", "GX12 AUX1 UART device")
 	stdin := flag.Bool("stdin", false, "read framed data from standard input")
 	startVideo := flag.Bool("start-video", false, "start fpv-video with Ground Station")
 	flag.Parse()
 
-	if *stdin == (*serialPath != "") {
-		log.Fatal("select exactly one of -stdin or -serial")
+	if *stdin && *startVideo {
+		log.Fatal("-stdin is intended for protocol tests; omit -start-video")
 	}
 
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
@@ -40,7 +40,7 @@ func main() {
 	var input io.Reader = os.Stdin
 	var port *os.File
 	var err error
-	if *serialPath != "" {
+	if !*stdin {
 		port, err = serialport.Open115200(*serialPath)
 		if err != nil {
 			log.Fatal(err)