ubuntu-串口编程-白红宇

ubuntu-串口编程

阅读量：6994 次

发布时间：2019-06-27

本文共 5796 字，大约阅读时间需要 19 分钟。

#include 
    
       #include 
     
        #include 
      
           #include 
       
          #include 
        
             #include 
         
           //set baud rate #include 
          
            #include 
           
             #include 
            
              #include 
             
               #include 
              
                //#define rec_buf_wait_2s 2 #define buffLen 1024 #define rcvTimeOut 2 /*******************************************************/ /**下面的函数暂时并没什么意思，完全可以忽略**/ int read_data_tty(int fd, char *rec_buf, int rec_wait) { int retval; fd_set rfds; struct timeval tv; int ret, pos; tv.tv_sec = rec_wait; tv.tv_usec = 0; pos = 0; while (1) { FD_ZERO(&rfds); FD_SET(fd, &rfds); retval = select(fd + 1, &rfds, NULL, NULL, &tv); if (retval == -1) { perror("select()"); break; } else if (retval) { ret = read(fd, rec_buf + pos, 2048); pos += ret; if (rec_buf[pos - 2] == '\r' && rec_buf[pos - 1] == '\n') { FD_ZERO(&rfds); FD_SET(fd, &rfds); retval = select(fd + 1, &rfds, NULL, NULL, &tv); if (!retval) { break; } } } else { break; } } return 1; } int device_485_receive(int fd) { int ret; char rec_buf[1024]; int i; char send_buf[] = { "02030202f925" }; for (i = 0; i<10; i++) { /*ret = write(fd, send_buf, strlen(send_buf)); if (ret == -1) { printf("write device %s error\n", device); return -1; }*/ //if (read_data_tty(fd, rec_buf, rec_buf_wait_2s)) { if (read_data_tty(fd, rec_buf,2)) { printf("%s\n", rec_buf); } else { printf("read_error\n"); } //if ((read(fd, rec_buf, strlen(rec_buf))) == -1) { // printf("error reading string\n"); // return -1; //} else { // printf("%s\n", rec_buf); } return 0; } /*-----------------------------------------------------*/ /*******************************************************/ /*************Linux and Serial Port *********************/ /*************Linux and Serial Port *********************/ int openPort(int fd, int comport) { if (comport == 1) { fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY); if (-1 == fd) { perror("Can't Open Serial Port"); return(-1); } else { printf("open ttyS0 .....\n"); } } else if (comport == 2) { fd = open("/dev/ttyS1", O_RDWR | O_NOCTTY | O_NDELAY); if (-1 == fd) { perror("Can't Open Serial Port"); return(-1); } else { printf("open ttyS1 .....\n"); } } else if (comport == 3) { fd = open("/dev/ttyS2", O_RDWR | O_NOCTTY | O_NDELAY); if (-1 == fd) { perror("Can't Open Serial Port"); return(-1); } else { printf("open ttyS2 .....\n"); } } /*************************************************/ else if (comport == 4) { fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY); if (-1 == fd) { perror("Can't Open Serial Port"); return(-1); } else { printf("open ttyUSB0 .....\n"); } } if (fcntl(fd, F_SETFL, 0)<0) { printf("fcntl failed!\n"); } else { printf("fcntl=%d\n", fcntl(fd, F_SETFL, 0)); } if (isatty(STDIN_FILENO) == 0) { printf("standard input is not a terminal device\n"); } else { printf("is a tty success!\n"); } printf("fd-open=%d\n", fd); return fd; } int setOpt(int fd, int nSpeed, int nBits, char nEvent, int nStop) { struct termios newtio, oldtio; if (tcgetattr(fd, &oldtio) != 0) { perror("SetupSerial 1"); return -1; } bzero(&newtio, sizeof(newtio)); newtio.c_cflag |= CLOCAL | CREAD; newtio.c_cflag &= ~CSIZE; switch (nBits) { case 7: newtio.c_cflag |= CS7; break; case 8: newtio.c_cflag |= CS8; break; } switch (nEvent) { case 'O': //奇校验 newtio.c_cflag |= PARENB; newtio.c_cflag |= PARODD; newtio.c_iflag |= (INPCK | ISTRIP); break; case 'E': //偶校验 newtio.c_iflag |= (INPCK | ISTRIP); newtio.c_cflag |= PARENB; newtio.c_cflag &= ~PARODD; break; case 'N': //无校验 newtio.c_cflag &= ~PARENB; break; } switch (nSpeed) { case 2400: cfsetispeed(&newtio, B2400); cfsetospeed(&newtio, B2400); break; case 4800: cfsetispeed(&newtio, B4800); cfsetospeed(&newtio, B4800); break; case 9600: cfsetispeed(&newtio, B9600); cfsetospeed(&newtio, B9600); break; case 115200: cfsetispeed(&newtio, B115200); cfsetospeed(&newtio, B115200); break; default: cfsetispeed(&newtio, B9600); cfsetospeed(&newtio, B9600); break; } if (nStop == 1) { newtio.c_cflag &= ~CSTOPB; } else if (nStop == 2) { newtio.c_cflag |= CSTOPB; } newtio.c_cc[VTIME] = 0; newtio.c_cc[VMIN] = 0; tcflush(fd, TCIFLUSH); if ((tcsetattr(fd, TCSANOW, &newtio)) != 0) { perror("com set error"); return -1; } printf("set done!\n"); return 0; } int readDataTty(int fd, char *rcv_buf, int TimeOut, int Len) { int retval; fd_set rfds; struct timeval tv; int ret, pos; tv.tv_sec = TimeOut / 1000; //set the rcv wait time tv.tv_usec = TimeOut % 1000 * 1000; //100000us = 0.1s pos = 0; while (1) { FD_ZERO(&rfds); FD_SET(fd, &rfds); retval = select(fd + 1, &rfds, NULL, NULL, &tv); if (retval == -1) { perror("select()"); break; } else if (retval) { ret = read(fd, rcv_buf + pos, 1); if (-1 == ret) { break; } pos++; if (Len <= pos) { break; } } else { break; } } return pos; } int sendDataTty(int fd, char *send_buf, int Len) { ssize_t ret; ret = write(fd, send_buf, Len); if (ret == -1) { printf("write device error\n"); return -1; } return 1; } int main(int argc, char** argv) { int iSetOpt = 0;//SetOpt 的增量i int fdSerial = 0; //openPort if ((fdSerial = openPort(fdSerial, 4))<0)//1--"/dev/ttyS0",2--"/dev/ttyS1",3--"/dev/ttyS2",4--"/dev/ttyUSB0" 小电脑上是2--"/dev/ttyS1" { perror("open_port error"); return -1; } if ((iSetOpt = setOpt(fdSerial, 115200, 8, 'N', 1))<0) { perror("set_opt error"); return -1; } printf("Serial fdSerial=%d\n", fdSerial); tcflush(fdSerial, TCIOFLUSH);//清掉串口缓存 fcntl(fdSerial, F_SETFL, 0); char buffRcvData[buffLen] = { 0 }; unsigned int readDataNum = 0; /* buffRcvData[0] = 's'; buffRcvData[1] = 't'; buffRcvData[2] = 'a'; buffRcvData[3] = 'r'; buffRcvData[4] = 't'; sendDataTty(fdSerial, buffRcvData, 5); */ while (1){ readDataNum = readDataTty(fdSerial, buffRcvData, rcvTimeOut, buffLen); sendDataTty(fdSerial, buffRcvData, readDataNum); } return 1; }