程序员探案之被吃掉的串口数据

1opt.c_iflag &= ~(ICRNL | INLCR);
2opt.c_iflag &= ~(IXON | IXOFF | IXANY);
3opt.c_oflag &= ~(ONLCR | OCRNL); 

  1/**
  2*打开串口
  3*/
  4int open_dev(char *dev_name)
  5{
  6    int fd = open(dev_name, O_RDWR | O_NOCTTY);
  7
  8    if (-1 == fd)
  9    {
 10        perror("Can't open serial port");
 11        return -1;
 12    }
 13    else
 14        return fd;
 15
 16}
 17
 18
 19/***设置串口通信速率和模式标识 
 20*@param  fd     类型 int  打开串口的文件句柄 
 21*@param  speed  类型 int  串口速度 
 22*@return  void*/
 23void set_speed(int fd, int speed)
 24{
 25    int i;
 26    int status;
 27    int speed_arr[] = {B921600, B460800, B230400, B115200, B57600,
 28                       B38400, B19200, B9600, B4800, B2400, B1200,
 29                       B300, B38400, B19200, B9600, B4800, B2400,
 30                       B1200, B300, };
 31    int name_arr[] = {921600, 460800, 230400, 115200, 57600, 38400,
 32                      19200, 9600, 4800, 2400, 1200, 300, 38400, 
 33                      19200,  9600, 4800, 2400, 1200, 300, };
 34    struct termios opt;
 35    tcgetattr(fd, &opt);
 36    opt.c_iflag &= ~ (INLCR | ICRNL | IGNCR);
 37    opt.c_oflag &= ~(ONLCR | OCRNL);
 38    opt.c_iflag &= ~(IXON);
 39    for ( i= 0; i < sizeof(speed_arr) / sizeof(int); i++)
 40    {
 41        if (speed == name_arr[i])
 42        {
 43            tcflush(fd, TCIOFLUSH);
 44            cfsetispeed(&opt, speed_arr[i]);
 45            cfsetospeed(&opt, speed_arr[i]);
 46            status = tcsetattr(fd, TCSANOW, &opt);
 47            if (status != 0)
 48                perror("tcsetattr fd");
 49            return;
 50        }
 51        tcflush(fd,TCIOFLUSH);
 52    }
 53}
 54
 55
 56/**
 57*设置串口数据位,停止位和效验位
 58*@param fd 类型 int 打开的串口文件句柄*
 59*@param databits 类型 int 数据位 取值 为 7 或者8*
 60*@param stopbits 类型 int 停止位 取值为 1 或者2*
 61*@param parity 类型 int 效验类型 取值为N,E,O,,S
 62*/
 63int set_Parity(int fd,int databits,int stopbits,int parity)
 64{
 65    struct termios options;
 66    if ( tcgetattr( fd,&options) != 0)
 67    {
 68        perror("tcgetattr error");
 69        return -5;
 70    }
 71    options.c_cflag &= ~CSIZE;
 72    options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
 73    options.c_oflag &= ~OPOST;
 74    switch (databits) /*设置数据位数*/
 75    {
 76    case 7:
 77        options.c_cflag |= CS7;
 78        break;
 79    case 8:
 80        options.c_cflag |= CS8;
 81        break;
 82    default:
 83        fprintf(stderr,"unsupported data size\n");
 84        return -4;
 85    }
 86    switch (parity)
 87    {
 88    case 'n':
 89    case 'N':
 90        options.c_cflag &= ~PARENB; /* Clear parity enable */
 91        options.c_iflag &= ~INPCK; /* Enable parity checking */
 92        break;
 93    case 'o':
 94    case 'O':
 95        options.c_cflag |= (PARODD | PARENB); /* 设置为奇效验*/
 96        options.c_iflag |= INPCK; /* Disnable parity checking */
 97        break;
 98    case 'e':
 99    case 'E':
100        options.c_cflag |= PARENB; /* Enable parity */
101        options.c_cflag &= ~PARODD; /* 转换为偶效验*/
102        options.c_iflag |= INPCK; /* Disnable parity checking */
103        break;
104    case 'S':
105    case 's': /*as no parity*/
106        options.c_cflag &= ~PARENB;
107        options.c_cflag &= ~CSTOPB;
108        break;
109    default:
110        fprintf(stderr,"unsupported parity\n");
111        return -3;
112    }
113    /* 设置停止位*/
114    switch (stopbits)
115    {
116    case 1:
117        options.c_cflag &= ~CSTOPB;
118        break;
119    case 2:
120        options.c_cflag |= CSTOPB;
121        break;
122    default:
123        fprintf(stderr,"unsupported stop bits\n");
124        return -2;
125    }
126    /* Set input parity option */
127    if (parity != 'n')
128        options.c_iflag |= INPCK;
129    options.c_cc[VTIME] = 0; // 15 seconds
130
131    options.c_cc[VMIN] = 0;
132
133    tcflush(fd,TCIFLUSH); /* Update the options and do it NOW */
134    if (tcsetattr(fd,TCSANOW,&options) != 0)
135    {
136        perror("setup serial options error");
137        return -1;
138    }
139    return 0;
140}