README
¶
go.bug.st/serial
A cross-platform serial library for go-lang.
Documentation and examples
See the godoc here: https://godoc.org/go.bug.st/serial
go.mod transition
This library now support go.mod with the import go.bug.st/serial.
If you came from the pre-go.mod era please update your import paths from go.bug.st/serial.v1 to go.bug.st/serial to receive new updates. Anyway, the latest v1 release should still be avaiable using the old import.
Credits
✨ Thanks to all awesome contributors! ✨
License
The software is release under a BSD 3-clause license
Documentation
¶
Overview ¶
Package serial is a cross-platform serial library for the go language.
The canonical import for this library is go.bug.st/serial so the import line is the following:
import "go.bug.st/serial"
It is possible to get the list of available serial ports with the GetPortsList function:
ports, err := serial.GetPortsList()
if err != nil {
log.Fatal(err)
}
if len(ports) == 0 {
log.Fatal("No serial ports found!")
}
for _, port := range ports {
fmt.Printf("Found port: %v\n", port)
}
The serial port can be opened with the Open function:
mode := &serial.Mode{
BaudRate: 115200,
}
port, err := serial.Open("/dev/ttyUSB0", mode)
if err != nil {
log.Fatal(err)
}
The Open function needs a "mode" parameter that specifies the configuration options for the serial port. If not specified the default options are 9600_N81, in the example above only the speed is changed so the port is opened using 115200_N81. The following snippets shows how to declare a configuration for 57600_E71:
mode := &serial.Mode{
BaudRate: 57600,
Parity: serial.EvenParity,
DataBits: 7,
StopBits: serial.OneStopBit,
}
The configuration can be changed at any time with the SetMode function:
err := port.SetMode(mode)
if err != nil {
log.Fatal(err)
}
The port object implements the io.ReadWriteCloser interface, so we can use the usual Read, Write and Close functions to send and receive data from the serial port:
n, err := port.Write([]byte("10,20,30\n\r"))
if err != nil {
log.Fatal(err)
}
fmt.Printf("Sent %v bytes\n", n)
buff := make([]byte, 100)
for {
n, err := port.Read(buff)
if err != nil {
log.Fatal(err)
break
}
if n == 0 {
fmt.Println("\nEOF")
break
}
fmt.Printf("%v", string(buff[:n]))
}
If a port is a virtual USB-CDC serial port (for example an USB-to-RS232 cable or a microcontroller development board) is possible to retrieve the USB metadata, like VID/PID or USB Serial Number, with the GetDetailedPortsList function in the enumerator package:
import "go.bug.st/serial/enumerator"
ports, err := enumerator.GetDetailedPortsList()
if err != nil {
log.Fatal(err)
}
if len(ports) == 0 {
fmt.Println("No serial ports found!")
return
}
for _, port := range ports {
fmt.Printf("Found port: %s\n", port.Name)
if port.IsUSB {
fmt.Printf(" USB ID %s:%s\n", port.VID, port.PID)
fmt.Printf(" USB serial %s\n", port.SerialNumber)
}
}
for details on USB port enumeration see the documentation of the specific package.
This library tries to avoid the use of the "C" package (and consequently the need of cgo) to simplify cross compiling. Unfortunately the USB enumeration package for darwin (MacOSX) requires cgo to access the IOKit framework. This means that if you need USB enumeration on darwin you're forced to use cgo.
Example (SendAndReceive) ¶
This example prints the list of serial ports and use the first one to send a string "10,20,30" and prints the response on the screen.
package main
import (
"fmt"
"log"
"strings"
"go.bug.st/serial"
)
func main() {
// Retrieve the port list
ports, err := serial.GetPortsList()
if err != nil {
log.Fatal(err)
}
if len(ports) == 0 {
log.Fatal("No serial ports found!")
}
// Print the list of detected ports
for _, port := range ports {
fmt.Printf("Found port: %v\n", port)
}
// Open the first serial port detected at 9600bps N81
mode := &serial.Mode{
BaudRate: 9600,
Parity: serial.NoParity,
DataBits: 8,
StopBits: serial.OneStopBit,
}
port, err := serial.Open(ports[0], mode)
if err != nil {
log.Fatal(err)
}
// Send the string "10,20,30\n\r" to the serial port
n, err := port.Write([]byte("10,20,30\n\r"))
if err != nil {
log.Fatal(err)
}
fmt.Printf("Sent %v bytes\n", n)
// Read and print the response
buff := make([]byte, 100)
for {
// Reads up to 100 bytes
n, err := port.Read(buff)
if err != nil {
log.Fatal(err)
}
if n == 0 {
fmt.Println("\nEOF")
break
}
fmt.Printf("%s", string(buff[:n]))
// If we receive a newline stop reading
if strings.Contains(string(buff[:n]), "\n") {
break
}
}
}
Output:
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var NoTimeout time.Duration = -1
NoTimeout should be used as a parameter to SetReadTimeout to disable timeout.
Functions ¶
func GetPortsList ¶
GetPortsList retrieve the list of available serial ports
Example ¶
package main
import (
"fmt"
"log"
"go.bug.st/serial"
)
func main() {
ports, err := serial.GetPortsList()
if err != nil {
log.Fatal(err)
}
if len(ports) == 0 {
fmt.Println("No serial ports found!")
} else {
for _, port := range ports {
fmt.Printf("Found port: %v\n", port)
}
}
}
Output:
Types ¶
type Mode ¶
type Mode struct {
BaudRate int // The serial port bitrate (aka Baudrate)
DataBits int // Size of the character (must be 5, 6, 7 or 8)
Parity Parity // Parity (see Parity type for more info)
StopBits StopBits // Stop bits (see StopBits type for more info)
InitialStatusBits *ModemOutputBits // Initial output modem bits status (if nil defaults to DTR=true and RTS=true)
}
Mode describes a serial port configuration.
type ModemOutputBits ¶ added in v1.4.0
ModemOutputBits contains all the modem output bits for a serial port. This is used in the Mode.InitialStatusBits struct to specify the initial status of the bits. Note: Linux and MacOSX (and basically all unix-based systems) can not set the status bits before opening the port, even if the initial state of the bit is set to false they will go anyway to true for a few milliseconds, resulting in a small pulse.
type ModemStatusBits ¶
type ModemStatusBits struct {
CTS bool // ClearToSend status
DSR bool // DataSetReady status
RI bool // RingIndicator status
DCD bool // DataCarrierDetect status
}
ModemStatusBits contains all the modem input status bits for a serial port (CTS, DSR, etc...). It can be retrieved with the Port.GetModemStatusBits() method.
type Port ¶
type Port interface {
// SetMode sets all parameters of the serial port
SetMode(mode *Mode) error
// Stores data received from the serial port into the provided byte array
// buffer. The function returns the number of bytes read.
//
// The Read function blocks until (at least) one byte is received from
// the serial port or an error occurs.
Read(p []byte) (n int, err error)
// Send the content of the data byte array to the serial port.
// Returns the number of bytes written.
Write(p []byte) (n int, err error)
// Wait until all data in the buffer are sent
Drain() error
// ResetInputBuffer Purges port read buffer
ResetInputBuffer() error
// ResetOutputBuffer Purges port write buffer
ResetOutputBuffer() error
// SetDTR sets the modem status bit DataTerminalReady
SetDTR(dtr bool) error
// SetRTS sets the modem status bit RequestToSend
SetRTS(rts bool) error
// GetModemStatusBits returns a ModemStatusBits structure containing the
// modem status bits for the serial port (CTS, DSR, etc...)
GetModemStatusBits() (*ModemStatusBits, error)
// SetReadTimeout sets the timeout for the Read operation or use serial.NoTimeout
// to disable read timeout.
SetReadTimeout(t time.Duration) error
// Close the serial port
Close() error
// Break sends a break for a determined time
Break(time.Duration) error
}
Port is the interface for a serial Port
type PortError ¶
type PortError struct {
// contains filtered or unexported fields
}
PortError is a platform independent error type for serial ports
func (PortError) Code ¶
func (e PortError) Code() PortErrorCode
Code returns an identifier for the kind of error occurred
func (PortError) EncodedErrorString ¶
EncodedErrorString returns a string explaining the error code
type PortErrorCode ¶
type PortErrorCode int
PortErrorCode is a code to easily identify the type of error
const ( // PortBusy the serial port is already in used by another process PortBusy PortErrorCode = iota // PortNotFound the requested port doesn't exist PortNotFound // InvalidSerialPort the requested port is not a serial port InvalidSerialPort // PermissionDenied the user doesn't have enough priviledges PermissionDenied // InvalidSpeed the requested speed is not valid or not supported InvalidSpeed // InvalidDataBits the number of data bits is not valid or not supported InvalidDataBits // InvalidParity the selected parity is not valid or not supported InvalidParity // InvalidStopBits the selected number of stop bits is not valid or not supported InvalidStopBits // InvalidTimeoutValue the timeout value is not valid or not supported InvalidTimeoutValue // ErrorEnumeratingPorts an error occurred while listing serial port ErrorEnumeratingPorts // PortClosed the port has been closed while the operation is in progress PortClosed // FunctionNotImplemented the requested function is not implemented FunctionNotImplemented )
Source Files
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Directories
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| Path | Synopsis |
|---|---|
|
Package enumerator is a golang cross-platform library for USB serial port discovery.
|
Package enumerator is a golang cross-platform library for USB serial port discovery. |
|
portlist is a tool to list all the available serial ports.
|
portlist is a tool to list all the available serial ports. |