c - 一根线串口通讯，回显错误

Question

我有一个单线串行通信接口(interface)，问题是我发送01010101，收到的回声是10次中的8次01010101，但10次中的2次我收到01110101。

代码示例:

void checkVersion(int fd) {
    tcflush(fd, TCIFLUSH);
    unsigned char checkVersion[] = {0x55, 0x02, 0x00, 0x02};
    int n = write(fd, &checkVersion, 4); //Send data
    if (n < 0) cout << "BM: WRITE FAILED" << endl;

    char read_bytes[10] = {0};
    char c;
    int aantalBytes = 0;
    bool foundU = false;
    int res;
    while (aantalBytes < 7) {
        res = read(fd, &c, 200);
        if (res != 0) {
            cout << "Byte received: " << bitset < 8 > (c) << endl;
            if (c == 'U')foundU = true;
            if (foundU)
                read_bytes[aantalBytes++] = c;
        }
        if (aantalBytes > 2 && !foundU) break;
    }
    if (!foundU) checkVersionSucceeded = false;
    if (read_bytes[aantalBytes - 3] == 0x02 && read_bytes[aantalBytes - 2] == 0x04 && read_bytes[aantalBytes - 1] == 0x06)
       cout << "BM Version 4" << endl;
}

如何配置我的端口:

int configure_port(int fd) // configure the port
{
    struct termios port_settings; // structure to store the port settings in

    cfsetispeed(&port_settings, B9600); // set baud rates
    cfsetospeed(&port_settings, B9600);

    port_settings.c_cflag &= ~PARENB; // set no parity, stop bits, data bits
    port_settings.c_cflag &= ~CSTOPB;
    port_settings.c_cflag &= ~CSIZE;
    port_settings.c_cflag |= CS8;

    tcsetattr(fd, TCSANOW, &port_settings); // apply the settings to the port
    return (fd);
} 

有什么问题吗？回声怎么可能 10 次中有 2 次混合？

Answer 1

也许您应该在配置连接时尝试使用 bzero() 函数。

bzero(&port_settings, sizeof (port_settings));

这会清除新端口设置的结构，这可能有助于阻止您通过串行端口收到的不规则答案。