Serial

A Go package to allow you to read and write from the serial port as a stream of bytes.

Updates by jkvatne.

Now includes parameter for interval timeout on windows. This makes it easier to implement reading of data from a remote unit. The original version would return only the first letter of a message when the interval timeout is set to ca 1 character time (11/baudrate).

I have also included a function to return all available ports on the computer. It can be found in enum_windows.go or enum_linux.go.

EnumerateSerialPorts() will return a list of ports and a list of description. The last list will only apear on windows. The descriptions are nice to have when determine which port to use, f.ex to avoid system-generated Bluetooth ports.

Details

It aims to have the same API on all platforms, including windows. As an added bonus, the windows package does not use cgo, so you can cross compile for windows from another platform.

You can cross compile with GOOS=windows GOARCH=386 go install github.com/tarm/serial

Currently there is very little in the way of configurability. You can set the baud rate. Then you can Read(), Write(), or Close() the connection. By default Read() will block until at least one byte is returned. Write is the same.

Currently all ports are opened with 8 data bits, 1 stop bit, no parity, no hardware flow control, and no software flow control. This works fine for many real devices and many faux serial devices including usb-to-serial converters and bluetooth serial ports.

You may Read() and Write() simulantiously on the same connection (from different goroutines).

Usage

package main

import (
        "log"

        "github.com/tarm/serial"
)

func main() {
        c := &serial.Config{Name: "COM45", Baud: 115200}
        s, err := serial.OpenPort(c)
        if err != nil {
                log.Fatal(err)
        }
        
        n, err := s.Write([]byte("test"))
        if err != nil {
                log.Fatal(err)
        }
        
        buf := make([]byte, 128)
        n, err = s.Read(buf)
        if err != nil {
                log.Fatal(err)
        }
        log.Printf("%q", buf[:n])
}

NonBlocking Mode

By default the returned Port reads in blocking mode. Which means Read() will block until at least one byte is returned. If that's not what you want, specify a positive ReadTimeout and the Read() will timeout returning 0 bytes if no bytes are read. Please note that this is the total timeout the read operation will wait and not the interval timeout between two bytes.

	c := &serial.Config{Name: "COM45", Baud: 115200, ReadTimeout: time.Second * 5}
	
	// In this mode, you will want to suppress error for read
	// as 0 bytes return EOF error on Linux / POSIX
	n, _ = s.Read(buf)

Possible Future Work

• better tests (loopback etc)