linux下串口控制
/* 本程序符合GPL条约
* Beneboy 2003-5-16
*/
#include <stdio.h> // printf
#include <fcntl.h> // open
#include <string.h> // bzero
#include <stdlib.h> // exit
#include <sys/times.h> // times
#include <sys/types.h> // pid_t
#include <termios.h> //termios, tcgetattr(), tcsetattr()
#include <unistd.h>
#include <sys/ioctl.h> // ioctl
#include "MyCom.h"
#define TTY_DEV "/dev/ttyS" //端口路径
//接收超时
#define TIMEOUT_SEC(buflen,baud) (buflen*20/baud+2)
#define TIMEOUT_USEC 0
/*******************************************
* 获得端口名称
********************************************/
char *get_ptty(pportinfo_t pportinfo)
{
char *ptty;
switch(pportinfo->tty){
case '0':{
ptty = TTY_DEV"0";
}break;
case '1':{
ptty = TTY_DEV"1";
}break;
case '2':{
ptty = TTY_DEV"2";
}break;
}
return(ptty);
}
/*******************************************
* 波特率转化转换函数
********************************************/
int convbaud(unsigned long int baudrate)
{
switch(baudrate){
case 2400:
return B2400;
case 4800:
return B4800;
case 9600:
return B9600;
case 19200:
return B19200;
case 38400:
return B38400;
case 57600:
return B57600;
case 115200:
return B115200;
default:
return B9600;
}
}
/*******************************************
* Setup comm attr
* fdcom: 串口文件描述符, pportinfo: 待设置的端口信息s
*
********************************************/
int PortSet(int fdcom, const pportinfo_t pportinfo)
{
struct termios termios_old, termios_new;
int baudrate, tmp;
char databit, stopbit, parity, fctl;
bzero(&termios_old, sizeof(termios_old));
bzero(&termios_new, sizeof(termios_new));
cfmakeraw(&termios_new);
tcgetattr(fdcom, &termios_old); //get the serial port attributions
/*------------设置端口属性----------------*/
//baudrates
baudrate = convbaud(pportinfo -> baudrate);
cfsetispeed(&termios_new, baudrate); //填入串口输入端波特率
cfsetospeed(&termios_new, baudrate); //填入串口输出端波特率
termios_new.c_cflag |= CLOCAL; //控制模式, 保证程序不会成为端口的占有者
termios_new.c_cflag |= CREAD; //控制模式, 使能端口读取输入的数据
// 控制模式, flow control
fctl = pportinfo-> fctl;
switch(fctl){
case '0':{
termios_new.c_cflag &= ~CRTSCTS; //no flow control
}break;
case '1':{
termios_new.c_cflag |= CRTSCTS; //hardware flow control
}break;
case '2':{
termios_new.c_iflag |= IXON | IXOFF |IXANY; //software flow control
}break;
}
//控制模式, data bits
termios_new.c_cflag &= ~CSIZE; //控制模式, 屏蔽字符大小位
databit = pportinfo -> databit;
switch(databit){
case '5':
termios_new.c_cflag |= CS5;
case '6':
termios_new.c_cflag |= CS6;
case '7':
termios_new.c_cflag |= CS7;
default:
termios_new.c_cflag |= CS8;
}
//控制模式 parity check
parity = pportinfo -> parity;
switch(parity){
case '0':{
termios_new.c_cflag &= ~PARENB; //no parity check
}break;
case '1':{
termios_new.c_cflag |= PARENB; //odd check
termios_new.c_cflag &= ~PARODD;
}break;
case '2':{
termios_new.c_cflag |= PARENB; //even check
termios_new.c_cflag |= PARODD;
}break;
}
//控制模式, stop bits
stopbit = pportinfo -> stopbit;
if(stopbit == '2'){
termios_new.c_cflag |= CSTOPB; //2 stop bits
}
else{
termios_new.c_cflag &= ~CSTOPB; //1 stop bits
}
//other attributions default
termios_new.c_oflag &= ~OPOST; //输出模式, 原始数据输出
termios_new.c_cc[VMIN] = 1; //控制字符, 所要读取字符的最小数量
termios_new.c_cc[VTIME] = 1; //控制字符, 读取第一个字符的等待时间, unit: (1/10)second
tcflush(fdcom, TCIFLUSH); //溢出的数据可以接收,但不读
tmp = tcsetattr(fdcom, TCSANOW, &termios_new); //设置新属性, TCSANOW: 所由改变立即生效
tcgetattr(fdcom, &termios_old);
return(tmp);
}
/*******************************************
* Open serial port
* tty: 端口号 ttyS0, ttyS1, ....
* 返回值为串口文件描述符
********************************************/
int PortOpen(pportinfo_t pportinfo)
{
int fdcom; //串口文件描述符
char *ptty;
ptty = get_ptty(pportinfo);
//fdcom = open(ptty, O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY);
fdcom = open(ptty, O_RDWR | O_NOCTTY | O_NONBLOCK);
return (fdcom);
}
/*******************************************
* Close serial port
********************************************/
void PortClose(int fdcom)
{
close(fdcom);
}
/********************************************
* send data
* fdcom: 串口描述符, data: 待发送数据, datalen: 数据长度
* 返回实际发送长度
*********************************************/
int PortSend(int fdcom, char *data, int datalen)
{
int len = 0;
len = write(fdcom, data, datalen); //实际写入的长度
if(len == datalen){
return (len);
}
else{
tcflush(fdcom, TCOFLUSH);
return -1;
}
}
/*******************************************
* receive data
* 返回实际读入的字节数
*
********************************************/
int PortRecv(int fdcom, char *data, int datalen, int baudrate)
{
int readlen, fs_sel;
fd_set fs_read;
struct timeval tv_timeout;
FD_ZERO(&fs_read);
FD_SET(fdcom, &fs_read);
tv_timeout.tv_sec = TIMEOUT_SEC(datalen, baudrate);
tv_timeout.tv_usec = TIMEOUT_USEC;
fs_sel = select(fdcom+1, &fs_read, NULL, NULL, &tv_timeout);
if(fs_sel){
readlen = read(fdcom, data, datalen);
return(readlen);
}
else{
return(-1);
}
return (readlen);
}
//*************************Test*********************************
int main(int argc, char *argv[])
{
int fdcom, i, SendLen, RecvLen;
struct termios termios_cur;
char RecvBuf[256];
char writeBuf[256];
portinfo_t portinfo ={
'0', // print prompt after receiving
9600, // baudrate: 9600
'8', // databit: 8
'0', // debug: off
'0', // echo: off
'2', // flow control: software
'0', // default tty: COM1
'0', // parity: none
'1', // stopbit: 1
0 // reserved
};
if(argc != 2){
printf("Usage: <type 0 -- send 1 -- receive>\n");
printf(" eg:");
printf(" MyPort 0");
exit(-1);
}
fdcom = PortOpen(&portinfo);
if(fdcom<0){
printf("Error: open serial port error.\n");
exit(1);
}
PortSet(fdcom, &portinfo);
while(1)
if(atoi(argv[1]) == 0)
{
//send data
//for(i=0; i<1000; i++)
{
//fgets(writeBuf,256,stdin);
scanf("%s",writeBuf);
SendLen = PortSend(fdcom, writeBuf, strlen(writeBuf));
if(SendLen>0)
{
//printf("send data %s", writeBuf);
}
else
{
printf("Error: send failed.\n");
}
if(strncmp(writeBuf,"exit",4)==0)
break;
sleep(1);
}
//PortClose(fdcom);
}
else
{
//for(;;)
{
RecvLen = PortRecv(fdcom, RecvBuf, 256, portinfo.baudrate);
if(RecvLen>0)
{
/*for(i=0; i<RecvLen; i++)
{
printf("Receive data No %d is %x.\n", i, RecvBuf[i]);
}//*/
RecvBuf[RecvLen] = '\0';
printf("read data %s\n",RecvBuf);
if(strncmp(RecvBuf,"exit",4)==0)
break;
}
else
{
//printf("Error: receive error.\n");
}
sleep(1);
}
}
PortClose(fdcom);
return 0;
}
