linux下串口通信代码

//清理串口设备资源
int cleanTTY(TTY_INFO *ptty)
{
//关闭打开的串口设备
if(ptty->fd>0)
{
tcsetattr(ptty->fd,TCSANOW,&ptty->otm);
close(ptty->fd);
ptty->fd = -1;
free(ptty);
ptty = NULL;
int setTTYParity(TTY_INFO *ptty,int databits,int parity,int stopbits);
int cleanTTY(TTY_INFO *ptty);
int sendnTTY(TTY_INFO *ptty,char *pbuf,int size);
int recvnTTY(TTY_INFO *ptty,char *pbuf,int size);
{
int ret,left,bytes;
left = size;
while(left>0)
{
ret = 0;
bytes = 0;
pthread_mutex_lock(&ptty->mt);
ioctl(ptty->fd, FIONREAD, &bytes);
if(bytes>0)
{
ret = read(ptty->fd,pbuf,left);
return 0;
}
//设置串口数据位，停止位和效验位
// ptty参数类型(TTY_INFO *),已经初始化的串口设备信息结构指针
// databits参数类型(int),数据位,取值为7或者8
// stopbits参数类型(int),停止位,取值为1或者2
// parity参数类型(int),效验类型取值为N,E,O,,S
if(ret >0)
{
nleft -= ret;
ptmp += ret;
}
//usleep(100);
}
return size - nleft;
}
int lockTTY(TTY_INFO *ptty)
{
if(ptty->fd < 0)
{
return 1;
int lockTTY(TTY_INFO *ptty);
int unlockTTY(TTY_INFO *ptty);
#endif
2.Stty.c
#include <stdio.h>
#include <sys/ioctl.h>
#include "stty.h"
///////////////////////////////////////////////////////////////////////////////
char name[24]; //串口设备名称，例："/dev/ttyS0"
struct termios ntm; //新的串口设备选项
struct termios otm; //旧的串口设备选项
} TTY_INFO;
//串口操作函数
TTY_INFO *readyTTY(int id);
int setTTYSpeed(TTY_INFO *ptty, int speed);
break;
case 'e':
case 'E':
ptty->ntm.c_cflag |= PARENB; /* Enable parity */
ptty->ntm.c_cflag &= ~PARODD; /*转换为偶效验*/
ptty->ntm.c_iflag |= INPCK; /* Disnable parity checking */
}
return 0;
}
///////////////////////////////////////////////////////////////////////////////
//设置串口通信速率
// ptty参数类型(TTY_INFO *),已经初始化的串口设备信息结构指针
// speed参数类型(int),用来设置串口的波特率
//初始化串口设备并进行原有设置的保存
TTY_INFO *readyTTY(int id)
{
TTY_INFO *ptty;
ptty = (TTY_INFO *)malloc(sizeof(TTY_INFO));
if(ptty == NULL)
return NULL;
memset(ptty,0,sizeof(TTY_INFO));
tcflush(ptty->fd, TCIFLUSH);
if (tcsetattr(ptty->fd,TCSANOW,&ptty->ntm) != 0)
{
printf("SetupSerial \n");
return 4;
}
return 0;
}
int recvnTTY(TTY_INFO *ptty,char *pbuf,int size)
ptty->ntm.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case 'o':
case 'O':
ptty->ntm.c_cflag |= (PARODD|PARENB); /*设置为奇效验*/
ptty->ntm.c_iflag |= INPCK; /* Disnable parity checking */
}
pthread_mutex_unlock(&ptty->mt);
if(ret >0)
{
left -= ret;
pbuf += ret;
}
usleep(100);
}
return size - left;
}
int sendnTTY(TTY_INFO *ptty,char *pbuf,int size)
// return返回值类型(int),函数执行成功返回零值，否则返回大于零的值
///////////////////////////////////////////////////////////////////////////////
int setTTYParity(TTY_INFO *ptty,int databits,int parity,int stopbits)
{
int ret,nleft;
char *ptmp;
ret = 0;
nleft = size;
ptmp = pbuf;
while(nleft>0)
{
pthread_mutex_lock(&ptty->mt);
ret = write(ptty->fd,ptmp,nleft);
pthread_mutex_unlock(&ptty->mt);
{
//取得串口设置
if( tcgetattr(ptty->fd,&ptty->ntm) != 0)
{
printf("SetupSerial [%s]\n",ptty->name);
return 1;
}
bzero(&ptty->ntm, sizeof(ptty->ntm));
ptty->ntm.c_cflag = CS8 | CLOCAL | CREAD;
ptty->ntm.c_iflag = IGNPAR;
ptty->ntm.c_oflag = 0;
//设置串口的各种参数
ptty->ntm.c_cflag &= ~CSIZE;
switch (databits)
{ //设置数据位数
case 7:
ptty->ntm.c_cflag |= CS7;
break;
// return返回值类型(int),函数执行成功返回零值，否则返回大于零的值
///////////////////////////////////////////////////////////////////////////////
int setTTYSpeed(TTY_INFO *ptty, int speed)
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
#include <pthread.h>
//串口设备信息结构
typedef struct tty_info_t
{
int fd; //串口设备ID
pthread_mutex_t mt; //线程同步互斥对象
break;
case 'S':
case 's': /*as no parity*/
ptty->ntm.c_cflag &= ~PARENB;
ptty->ntm.c_cflag &= ~CSTOPB;
break;
default:
printf("Unsupported parity\n");
rቤተ መጻሕፍቲ ባይዱturn 2;
ptty->ntm.c_cflag |= B115200;
break;
}
ptty->ntm.c_iflag = IGNPAR;
ptty->ntm.c_oflag = 0;
tcflush(ptty->fd, TCIFLUSH);
tcsetattr(ptty->fd,TCSANOW,&ptty->ntm);
case 8:
ptty->ntm.c_cflag |= CS8;
break;
default:
printf("Unsupported data size\n");
return 5;
}
switch (parity)
{ //设置奇偶校验位数
case 'n':
case 'N':
ptty->ntm.c_cflag &= ~PARENB; /* Clear parity enable */
{
case 300:
ptty->ntm.c_cflag |= B300;
break;
case 1200:
ptty->ntm.c_cflag |= B1200;
break;
case 2400:
ptty->ntm.c_cflag |= B2400;
break;
case 4800:
ptty->ntm.c_cflag |= B4800;
}
//
//设置停止位
switch (stopbits)
{
case 1:
ptty->ntm.c_cflag &= ~CSTOPB;
break;
case 2:
ptty->ntm.c_cflag |= CSTOPB;
break;
default:
printf("Unsupported stop bits\n");
pthread_mutex_init(&ptty->mt,NULL);
sprintf(ptty->name,"/dev/ttyUSB%d",id);
printf("%s\n",ptty->name);
//打开并且设置串口
ptty->fd = open(ptty->name, O_RDWR | O_NOCTTY |O_NDELAY);
1.Stty.h
#ifndef __STTY_H__
#define __STTY_H__
//包含头文件
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
if (ptty->fd <0)
{
free(ptty);
return NULL;
}
//取得并且保存原来的设置
tcgetattr(ptty->fd,&ptty->otm);
//add by maxiang
return ptty;
}
///////////////////////////////////////////////////////////////////////////////
break;
case 9600:
ptty->ntm.c_cflag |= B9600;
break;
case 19200:
ptty->ntm.c_cflag |= B19200;
break;
case 38400:
ptty->ntm.c_cflag |= B38400;
break;
case 115200:
{
int i;
//进行新的串口设置,数据位为8位
bzero(&ptty->ntm, sizeof(ptty->ntm));
tcgetattr(ptty->fd,&ptty->ntm);
ptty->ntm.c_cflag = /*CS8 |*/ CLOCAL | CREAD;
switch(speed)
return 3;
}
ptty->ntm.c_lflag = 0;
ptty->ntm.c_cc[VTIME] = 0; // inter-character timer unused
ptty->ntm.c_cc[VMIN] = 1; // blocking read until 1 chars received