stty.c

一个串口的代码提供给大家参考。一个串口的代码提供给大家参考。

//stty.c

#include <stdio.h>
#include <sys/ioctl.h>
#include 'stty.h'

///////////////////////////////////////////////////////////////////////////////
// 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));
    pthread_mutex_init(&ptty->mt,NULL);
    sprintf(ptty->name,'/dev/ttyS%d',id);
    //
    // 打开并且设置串口
    ptty->fd = open(ptty->name, O_RDWR | O_NOCTTY |O_NDELAY);
    if (ptty->fd <0)
    {
        free(ptty);
        return NULL;
    }
    //
    // 取得并且保存原来的设置
    tcgetattr(ptty->fd,&ptty->otm);
    return ptty;
}

///////////////////////////////////////////////////////////////////////////////
// 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;
    }

    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
// 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)
{
    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)
    {
    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;
        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:
        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);
    //
    //
    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
// 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)
{
    //
    // 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;
    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 */
        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 */
        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 */
        break;
    case 'S':
    case 's': /*as no parity*/ 
        ptty->ntm.c_cflag &= ~PARENB;
        ptty->ntm.c_cflag &= ~CSTOPB;
        break;
    default: 
        printf('Unsupported parity\n');
        return 2;
    }
    //
    // 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');
        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
    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)//收（读）
{
    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);
        }
        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)//发（写）
{
    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);

        if(ret >0)
        {
            nleft -= ret;
            ptmp += ret;
        }
        //usleep(100);
    }

    return size - nleft;
}
int lockTTY(TTY_INFO *ptty)
{
    if(ptty->fd < 0)
    {
        return 1;
    }

    return flock(ptty->fd,LOCK_EX);
}
int unlockTTY(TTY_INFO *ptty)
{
    if(ptty->fd < 0)
    {
        return 1;
    }

    return flock(ptty->fd,LOCK_UN);
}


#ifdef LEAF_TTY_TEST
///////////////////////////////////////////////////////////////////////////////
// 接口测试
int main(int argc,char **argv)
{
    TTY_INFO *ptty;
    int nbyte,idx;
    unsigned char cc[16];
    
    ptty = readyTTY(0);//打开com1?
    if(ptty == NULL)
    {
        printf('readyTTY(0) error\n');
        return 1;
    }
    //
    //
    lockTTY(ptty);
    if(setTTYSpeed(ptty,19200)>0)
    {
        printf('setTTYSpeed() error\n');
        return -1;
    }
    if(setTTYParity(ptty,8,'N',1)>0)
    {
        printf('setTTYParity() error\n');
        return -1;
    }
    //
    
    
    //写触摸屏的停止位‘0’
    //暂停250ms
    //sleep(250);
    //写触摸屏的状态查询位‘*‘
    //查看收到的数据是否为“0xc0”
    //定坐标
    //写触摸屏的采样位‘1’
    
    idx = 0;
    while(1)
    {
        cc[0] = 0xFA;
        sendnTTY(ptty,&cc[0],1);
        nbyte = recvnTTY(ptty,cc,1);
        printf('%d:%02X\n',idx++,cc[0]);
    }

    cleanTTY(ptty);

}
#endif