c++ - C、Linux 中的串口读取/打开错误

Question

我在为要打开的串行端口选择正确的设置时遇到问题。我掌握的信息如下:

• 同步:异步方法
• 通讯方式:全双工传输
• 通信速度:9600 bps(每秒位数)
• 传输代码:8位数据
• 数据配置:起始位1，数据8位+奇偶校验1，停止位1
• 错误控制:水平 (CRC) 和垂直(偶数)奇偶校验
• 1字节配置在此连接时，PC 不应使用控制信号(DTR、DSR、RTS 和 CTS)。

我所拥有的是这样的:

bool configurePort(void)   {
    struct termios port_settings;
    bzero(&port_settings, sizeof(port_settings));

    tcgetattr(fd, &port_settings);

    cfsetispeed(&port_settings, B9600);
    cfsetospeed(&port_settings, B9600);

    port_settings.c_cflag &= ~CSIZE;
    port_settings.c_cflag |= CS8;

    // parity bit
    //port_settings.c_cflag &= ~PARENB;
    //port_settings.c_cflag &= ~PARODD;
    // hardware flow
    port_settings.c_cflag &= ~CRTSCTS;
    // stop bit
    //port_settings.c_cflag &= ~CSTOPB;

    port_settings.c_iflag = IGNBRK;
    port_settings.c_iflag &= ~(IXON | IXOFF | IXANY);
    port_settings.c_lflag = 0;
    port_settings.c_oflag = 0;

    port_settings.c_cc[VMIN] = 1;   
    port_settings.c_cc[VTIME] = 0;
    port_settings.c_cc[VEOF] = 4;   

    tcsetattr(fd, TCSANOW, &port_settings);


    return true;
}

尝试了各种修改，但似乎没有任何效果。

该设备通过 USB 串行 (ttyUSB0) 连接，并且我有权限。它打开设备，发送(？)数据，但永远不会返回任何内容......

有人能指出我应该做什么吗？

Answer 1

试试这个:

bool configurePort(void)   {
    struct termios port_settings;
    bzero(&port_settings, sizeof(port_settings));

    if(tcgetattr(fd, &port_settings) < 0) {
        perror("tcgetattr");
        return false;
    }

    cfmakeraw(&port_settings);

    cfsetispeed(&port_settings, B9600);
    cfsetospeed(&port_settings, B9600);

    //input
    port_settings.c_iflag &= ~(IXON | IXOFF | IXANY); //disable flow control

    //local
    port_settings.c_lflag = 0;  // No local flags

    //output
    port_settings.c_oflag |= ONLRET;
    port_settings.c_oflag |= ONOCR;
    port_settings.c_oflag &= ~OPOST;


    port_settings.c_cflag &= ~CRTSCTS; // Disable RTS/CTS    
    port_settings.c_cflag |= CREAD; // Enable receiver
    port_settings.c_cflag &= ~CSTOPB;


    tcflush(fd, TCIFLUSH);


    if(tcsetattr(fd, TCSANOW, &port_settings) < 0) {
        perror("tcsetattr");
        return false;
    }

    int iflags = TIOCM_DTR;
    ioctl(fd, TIOCMBIC, &iflags); // turn off DTR

    return true;
} //configure port