274 lines
7.3 KiB
Go
274 lines
7.3 KiB
Go
//
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// Copyright 2014 Cristian Maglie. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//
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package serial // import "go.bug.st/serial"
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/*
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// MSDN article on Serial Communications:
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// http://msdn.microsoft.com/en-us/library/ff802693.aspx
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// Arduino Playground article on serial communication with Windows API:
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// http://playground.arduino.cc/Interfacing/CPPWindows
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*/
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import "syscall"
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// opaque type that implements SerialPort interface for Windows
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type windowsSerialPort struct {
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Handle syscall.Handle
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}
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//sys RegEnumValue(key syscall.Handle, index uint32, name *uint16, nameLen *uint32, reserved *uint32, class *uint16, value *uint16, valueLen *uint32) (regerrno error) = advapi32.RegEnumValueW
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func GetPortsList() ([]string, error) {
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subKey, err := syscall.UTF16PtrFromString("HARDWARE\\DEVICEMAP\\SERIALCOMM\\")
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if err != nil {
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return nil, &SerialPortError{code: ERROR_ENUMERATING_PORTS}
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}
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var h syscall.Handle
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if syscall.RegOpenKeyEx(syscall.HKEY_LOCAL_MACHINE, subKey, 0, syscall.KEY_READ, &h) != nil {
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return nil, &SerialPortError{code: ERROR_ENUMERATING_PORTS}
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}
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defer syscall.RegCloseKey(h)
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var valuesCount uint32
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if syscall.RegQueryInfoKey(h, nil, nil, nil, nil, nil, nil, &valuesCount, nil, nil, nil, nil) != nil {
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return nil, &SerialPortError{code: ERROR_ENUMERATING_PORTS}
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}
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list := make([]string, valuesCount)
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for i := range list {
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var data [1024]uint16
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dataSize := uint32(len(data))
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var name [1024]uint16
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nameSize := uint32(len(name))
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if RegEnumValue(h, uint32(i), &name[0], &nameSize, nil, nil, &data[0], &dataSize) != nil {
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return nil, &SerialPortError{code: ERROR_ENUMERATING_PORTS}
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}
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list[i] = syscall.UTF16ToString(data[:])
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}
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return list, nil
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}
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func (port *windowsSerialPort) Close() error {
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return syscall.CloseHandle(port.Handle)
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}
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func (port *windowsSerialPort) Read(p []byte) (int, error) {
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var readed uint32
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params := &DCB{}
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for {
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if err := syscall.ReadFile(port.Handle, p, &readed, nil); err != nil {
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return int(readed), err
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}
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if readed > 0 {
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return int(readed), nil
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}
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// At the moment it seems that the only reliable way to check if
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// a serial port is alive in Windows is to check if the SetCommState
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// function fails.
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GetCommState(port.Handle, params)
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if err := SetCommState(port.Handle, params); err != nil {
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port.Close()
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return 0, err
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}
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}
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}
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func (port *windowsSerialPort) Write(p []byte) (int, error) {
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var writed uint32
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err := syscall.WriteFile(port.Handle, p, &writed, nil)
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return int(writed), err
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}
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const (
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DCB_BINARY = 0x00000001
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DCB_PARITY = 0x00000002
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DCB_OUT_X_CTS_FLOW = 0x00000004
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DCB_OUT_X_DSR_FLOW = 0x00000008
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DCB_DTR_CONTROL_DISABLE_MASK = ^0x00000030
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DCB_DTR_CONTROL_ENABLE = 0x00000010
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DCB_DTR_CONTROL_HANDSHAKE = 0x00000020
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DCB_DSR_SENSITIVITY = 0x00000040
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DCB_TX_CONTINUE_ON_XOFF = 0x00000080
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DCB_OUT_X = 0x00000100
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DCB_IN_X = 0x00000200
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DCB_ERROR_CHAR = 0x00000400
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DCB_NULL = 0x00000800
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DCB_RTS_CONTROL_DISABLE_MASK = ^0x00003000
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DCB_RTS_CONTROL_ENABLE = 0x00001000
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DCB_RTS_CONTROL_HANDSHAKE = 0x00002000
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DCB_RTS_CONTROL_TOGGLE = 0x00003000
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DCB_ABORT_ON_ERROR = 0x00004000
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)
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type DCB struct {
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DCBlength uint32
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BaudRate uint32
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// Flags field is a bitfield
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// fBinary :1
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// fParity :1
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// fOutxCtsFlow :1
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// fOutxDsrFlow :1
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// fDtrControl :2
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// fDsrSensitivity :1
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// fTXContinueOnXoff :1
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// fOutX :1
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// fInX :1
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// fErrorChar :1
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// fNull :1
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// fRtsControl :2
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// fAbortOnError :1
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// fDummy2 :17
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Flags uint32
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wReserved uint16
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XonLim uint16
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XoffLim uint16
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ByteSize byte
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Parity byte
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StopBits byte
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XonChar byte
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XoffChar byte
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ErrorChar byte
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EofChar byte
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EvtChar byte
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wReserved1 uint16
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}
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type COMMTIMEOUTS struct {
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ReadIntervalTimeout uint32
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ReadTotalTimeoutMultiplier uint32
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ReadTotalTimeoutConstant uint32
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WriteTotalTimeoutMultiplier uint32
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WriteTotalTimeoutConstant uint32
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}
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//sys GetCommState(handle syscall.Handle, dcb *DCB) (err error)
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//sys SetCommState(handle syscall.Handle, dcb *DCB) (err error)
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//sys SetCommTimeouts(handle syscall.Handle, timeouts *COMMTIMEOUTS) (err error)
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const (
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NOPARITY = 0 // Default
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ODDPARITY = 1
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EVENPARITY = 2
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MARKPARITY = 3
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SPACEPARITY = 4
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)
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const (
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ONESTOPBIT = 0 // Default
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ONE5STOPBITS = 1
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TWOSTOPBITS = 2
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)
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func (port *windowsSerialPort) SetMode(mode *Mode) error {
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params := DCB{}
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if err := GetCommState(port.Handle, ¶ms); err != nil {
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port.Close()
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return &SerialPortError{code: ERROR_INVALID_SERIAL_PORT}
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}
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if mode.BaudRate == 0 {
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params.BaudRate = 9600 // Default to 9600
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} else {
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params.BaudRate = uint32(mode.BaudRate)
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}
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if mode.DataBits == 0 {
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params.ByteSize = 8 // Default to 8 bits
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} else {
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params.ByteSize = byte(mode.DataBits)
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}
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params.StopBits = byte(mode.StopBits)
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params.Parity = byte(mode.Parity)
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if err := SetCommState(port.Handle, ¶ms); err != nil {
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port.Close()
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return &SerialPortError{code: ERROR_INVALID_SERIAL_PORT}
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}
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return nil
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}
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func OpenPort(portName string, mode *Mode) (SerialPort, error) {
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portName = "\\\\.\\" + portName
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path, err := syscall.UTF16PtrFromString(portName)
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if err != nil {
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return nil, err
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}
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handle, err := syscall.CreateFile(
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path,
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syscall.GENERIC_READ|syscall.GENERIC_WRITE,
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0, nil,
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syscall.OPEN_EXISTING,
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0, //syscall.FILE_FLAG_OVERLAPPED,
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0)
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if err != nil {
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switch err {
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case syscall.ERROR_ACCESS_DENIED:
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return nil, &SerialPortError{code: ERROR_PORT_BUSY}
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case syscall.ERROR_FILE_NOT_FOUND:
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return nil, &SerialPortError{code: ERROR_PORT_NOT_FOUND}
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}
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return nil, err
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}
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// Create the serial port
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port := &windowsSerialPort{
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Handle: handle,
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}
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// Set port parameters
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if err := port.SetMode(mode); err != nil {
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port.Close()
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return nil, &SerialPortError{code: ERROR_INVALID_SERIAL_PORT}
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}
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params := &DCB{}
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err = GetCommState(port.Handle, params)
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if err != nil {
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port.Close()
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return nil, &SerialPortError{code: ERROR_INVALID_SERIAL_PORT}
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}
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params.Flags |= DCB_RTS_CONTROL_ENABLE | DCB_DTR_CONTROL_ENABLE
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params.Flags &= ^uint32(DCB_OUT_X_CTS_FLOW)
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params.Flags &= ^uint32(DCB_OUT_X_DSR_FLOW)
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params.Flags &= ^uint32(DCB_DSR_SENSITIVITY)
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params.Flags |= DCB_TX_CONTINUE_ON_XOFF
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params.Flags &= ^uint32(DCB_IN_X | DCB_OUT_X)
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params.Flags &= ^uint32(DCB_ERROR_CHAR)
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params.Flags &= ^uint32(DCB_NULL)
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params.Flags &= ^uint32(DCB_ABORT_ON_ERROR)
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params.XonLim = 2048
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params.XoffLim = 512
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params.XonChar = 17 // DC1
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params.XoffChar = 19 // C3
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err = SetCommState(port.Handle, params)
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if err != nil {
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port.Close()
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return nil, &SerialPortError{code: ERROR_INVALID_SERIAL_PORT}
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}
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// Set timeouts to 1 second
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timeouts := &COMMTIMEOUTS{
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ReadIntervalTimeout: 0xFFFFFFFF,
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ReadTotalTimeoutMultiplier: 0xFFFFFFFF,
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ReadTotalTimeoutConstant: 1000, // 1 sec
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WriteTotalTimeoutConstant: 0,
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WriteTotalTimeoutMultiplier: 0,
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}
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if err := SetCommTimeouts(port.Handle, timeouts); err != nil {
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port.Close()
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return nil, &SerialPortError{code: ERROR_INVALID_SERIAL_PORT}
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}
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return port, nil
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}
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// vi:ts=2
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