c++ - 无法在 Ubuntu、C++ 上配置设备 ttyUSB0 (Arduino)

Question

我可以打开串行端口，但我无法正确配置此端口进行写入 (/dev/ttyUSB0)。

一段C++代码:

int
Platform::initConnection( const char* devicePath, int baudRate )
{
        int fd = 0;
        int ret = 0;

        struct termios terminalOptions;         // POSIX structure for configurating terminal devices

        fd = open( devicePath, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH );
        //fd = open( devicePath, O_RDWR | O_NOCTTY );
        if (fd == -1)
        {
                this->setFail();
                this->setErrorStr( "Failed to open: " + (std::string)devicePath + ". " + (std::string)strerror(errno) );

                return -1;
        }

        memset( &terminalOptions, 0, sizeof( struct termios ) );        // Cleaning up the structure
        cfmakeraw(&terminalOptions);                                    //

        cfsetspeed(&terminalOptions, baudRate);

        /*terminalOptions.c_cflag = CLOCAL;       // If CLOCAL is set, the line behaves as if DCD is always asserted.
                                                // It is used when your device is local

        terminalOptions.c_cflag |= CS8;         // Character size mask

        terminalOptions.c_cc[VMIN] = 24;         // 1 second timeout
        terminalOptions.c_cc[VTIME] = 0;       // */

        terminalOptions.c_cflag &= ~CRTSCTS;    
        terminalOptions.c_cflag |= (CLOCAL | CREAD);                   
        terminalOptions.c_iflag |= (IGNPAR | IGNCR);                  
        terminalOptions.c_iflag &= ~(IXON | IXOFF | IXANY);          
        terminalOptions.c_oflag &= ~OPOST;

        terminalOptions.c_cflag &= ~CSIZE;            
        terminalOptions.c_cflag |= CS8;              
        terminalOptions.c_cflag &= ~PARENB;         
        terminalOptions.c_iflag &= ~INPCK;         
        terminalOptions.c_iflag &= ~(ICRNL|IGNCR);
        terminalOptions.c_cflag &= ~CSTOPB;      
        terminalOptions.c_iflag |= INPCK;       
        terminalOptions.c_cc[VTIME] = 0.001;  //  1s=10   0.1s=1 *
        terminalOptions.c_cc[VMIN] = 0;


        ret = ioctl( fd, TIOCSETA, &terminalOptions );  // Configuring the device
        if (ret == -1)
        {
                this->setFail();
                this->setErrorStr( "Failed to configure device: " + (std::string)devicePath + ". " + (std::string)strerror(errno) );

                return -1;
        }

        return fd;
}

错误:

Failed to configure device: /dev/ttyUSB0. Inappropriate ioctl for device

Arduino UNO 使用芯片组 CH340。

我不知道如何解决这个问题。我希望得到你的帮助。谢谢!

更新:从 dmesg 登录

[11840.346071] usb 2-1.2: new full-speed USB device number 5 using ehci-pci
[11840.439832] usb 2-1.2: New USB device found, idVendor=1a86, idProduct=7523
[11840.439844] usb 2-1.2: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[11840.439850] usb 2-1.2: Product: USB2.0-Serial
[11840.440472] ch341 2-1.2:1.0: ch341-uart converter detected
[11840.442452] usb 2-1.2: ch341-uart converter now attached to ttyUSB0

Answer 1

感谢大家。我自己找到了解决方案:

1. 由于串行连接上的自动重置在大多数开发板上默认处于激活状态，如果您想使用最后一个命令而不是终端仿真器(arduino IDE、屏幕、picocom...)直接与您的开发板通信，则需要禁用此功能。 ).如果你有一 block Leonardo 板，你不必担心这一点，因为它不会自动重置。如果您有 Uno 板，请在 RESET 和 GND 引脚之间连接一个 10 µF 电容器。如果您有另一 block 板，请在 RESET 和 5V 引脚之间连接一个 120 欧姆的电阻。参见 http://playground.arduino.cc/Main/DisablingAutoResetOnSerialConnection了解更多详情。

2. 更改代码

   memset( &terminalOptions, 0, sizeof( struct termios ) );
   tcgetattr(fd, &terminalOptions);        //change
   cfmakeraw(&terminalOptions);
   cfsetspeed(&terminalOptions, baudRate);
   terminalOptions.c_cflag = CLOCAL;                                            
   terminalOptions.c_cflag |= CS8;        
   terminalOptions.c_cc[VMIN] = 0;         
   terminalOptions.c_cc[VTIME] = 10;      
   terminalOptions.c_cflag = CLOCAL;                                             
   terminalOptions.c_cflag &= ~HUPCL;       //change (disable hang-up-on-close to avoid reset)
   
   ret = tcsetattr(fd, TCSANOW, &terminalOptions);  //change
   if (ret == -1)
   {
           this->setFail();
           this->setErrorStr( "Failed to configure device: " + (std::string)devicePath + ". " + (std::string)strerror(errno) );
   
           return -1;
   }
   
   return fd;