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serial.go
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serial.go
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/*
serial 是一个Go代码实现的串口(Uart)收发包。使用操作系统标准的 read 和 write 文件接口
实现串口字节流的接收和发送。
默认配置: 8 N 1 N (数据位: 8 奇偶校验: N 停止位: 1 数据流控: N)
例子:
package main
import (
"github.com/xluohome/serial"
"log"
)
func main() {
c := &serial.Config{Name: "COM9", Baud: 9600}
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.Print("%q", buf[:n])
}
*/
package serial
import (
"errors"
"time"
)
const DefaultSize = 8 // Default value for Config.Size
type StopBits byte
type Parity byte
const (
Stop1 StopBits = 1
Stop1Half StopBits = 15
Stop2 StopBits = 2
)
const (
ParityNone Parity = 'N'
ParityOdd Parity = 'O'
ParityEven Parity = 'E'
ParityMark Parity = 'M' // parity bit is always 1
ParitySpace Parity = 'S' // parity bit is always 0
)
// Config contains the information needed to open a serial port.
//
// Currently few options are implemented, but more may be added in the
// future (patches welcome), so it is recommended that you create a
// new config addressing the fields by name rather than by order.
//
// For example:
//
// c0 := &serial.Config{Name: "COM45", Baud: 115200, ReadTimeout: time.Millisecond * 500}
// or
// c1 := new(serial.Config)
// c1.Name = "/dev/tty.usbserial"
// c1.Baud = 115200
// c1.ReadTimeout = time.Millisecond * 500
//
type Config struct {
Name string
Baud int
ReadTimeout time.Duration // Total timeout
// Size is the number of data bits. If 0, DefaultSize is used.
Size byte
// Parity is the bit to use and defaults to ParityNone (no parity bit).
Parity Parity
// Number of stop bits to use. Default is 1 (1 stop bit).
StopBits StopBits
// RTSFlowControl bool
// DTRFlowControl bool
// XONFlowControl bool
// CRLFTranslate bool
}
// ErrBadSize is returned if Size is not supported.
var ErrBadSize error = errors.New("unsupported serial data size")
// ErrBadStopBits is returned if the specified StopBits setting not supported.
var ErrBadStopBits error = errors.New("unsupported stop bit setting")
// ErrBadParity is returned if the parity is not supported.
var ErrBadParity error = errors.New("unsupported parity setting")
// OpenPort opens a serial port with the specified configuration
func OpenPort(c *Config) (*Port, error) {
size, par, stop := c.Size, c.Parity, c.StopBits
if size == 0 {
size = DefaultSize
}
if par == 0 {
par = ParityNone
}
if stop == 0 {
stop = Stop1
}
return openPort(c.Name, c.Baud, size, par, stop, c.ReadTimeout)
}
// Converts the timeout values for Linux / POSIX systems
func posixTimeoutValues(readTimeout time.Duration) (vmin uint8, vtime uint8) {
const MAXUINT8 = 1<<8 - 1 // 255
// set blocking / non-blocking read
var minBytesToRead uint8 = 1
var readTimeoutInDeci int64
if readTimeout > 0 {
// EOF on zero read
minBytesToRead = 0
// convert timeout to deciseconds as expected by VTIME
readTimeoutInDeci = (readTimeout.Nanoseconds() / 1e6 / 100)
// capping the timeout
if readTimeoutInDeci < 1 {
// min possible timeout 1 Deciseconds (0.1s)
readTimeoutInDeci = 1
} else if readTimeoutInDeci > MAXUINT8 {
// max possible timeout is 255 deciseconds (25.5s)
readTimeoutInDeci = MAXUINT8
}
}
return minBytesToRead, uint8(readTimeoutInDeci)
}
// func SendBreak()
// func RegisterBreakHandler(func())