Question

我正在从微控制器（LPC1549 XpressoV2）串行读取ADC和DAC值。已经有可用c编写的可用固件，我正在使用Python为Linux创建一个接口。为了交流，我正在使用Pyserial库。

打开端口后，当我从主机（PC）将数据发送到设备（微控制器）时，它应该发送回相同的数据“ ??????????”。一旦完成，它期望数据的特殊序列“（？，00100000,4095）”调用特定函数。

问题：打开端口后，我会收到我发送到设备的任何内容。它没有调用我要调用的特定函数并获得响应。

    import serial
    PC_HELLO   = "??????????"
    SINE_MODE  = "(?,00100000,4095)"
    SERIALPORT = "/dev/ttyACM0"
    BAUDRATE = 115200

    ser = serial.Serial(SERIALPORT, BAUDRATE)
    ser.bytesize = serial.EIGHTBITS #number of bits per bytes
    ser.parity = serial.PARITY_NONE #set parity check: no parity
    ser.stopbits = serial.STOPBITS_ONE #number of stop bits
    ser.timeout = 2              #timeout block read
    ser.xonxoff = False     #disable software flow control
    ser.rtscts = False     #disable hardware (RTS/CTS) flow control
    ser.dsrdtr = False       #disable hardware (DSR/DTR) flow control
    ser.writeTimeout = 0     #timeout for write

    print ('Starting Up Serial Monitor')

    try:
ser.open()

    except IOError as  e:
print("error open serial port: " + str(e))
ser.close()
ser.open()
pass
print("port was already open, was closed and opened again!")

    if ser.isOpen():

try:
        ser.flushInput()                 #flush input buffer, discarding all its contents
        ser.flushOutput()                #flush output buffer, aborting current output
        ser.write(PC_HELLO.encode())
        print("PC hello command is being written.. ")
        while True:

            try:
                ser.write(SINE_MODE.encode('ascii'))
                response = ser.readline()
                print(response)
            except KeyboardInterrupt as e:
                print("closing port ... keyboard interupt initiated..")
                ser.close()
                print('serial port is closed ...')

except Exception as e:
    print ("error communicating...: " + str(e))

    else:
print("cannot open serial port ")

C代码如下。 //这是NXP的示例代码

    while (1)
    {
// Check if host has connected and opened the VCOM port
if ((vcom_connected() != 0) && (prompt == 0))
{
  prompt = 1;
}
// If VCOM port is opened echo whatever we receive back to host
if (prompt)
{
  rdCnt = vcom_bread(&g_rxBuff[0], 256);  //i don't quite understand this line of code ;)
  if (rdCnt)
  {
    // character received
    uint8_t ch = g_rxBuff[0];

    // command start
    if (ch == '(')
    {
      wrCnt  = 0;
      wrStat = true;
    }

    // command transmitting
    if (wrStat)
    {
      // copy
      Data_string[wrCnt++] = ch;

      // command end
      if ((ch == ')') || (wrCnt > 17))
      {
        wrStat  = false;
        cmdStat = true;
      }
    }

    // command received
    if (cmdStat)
    {
      cmdStat = false;

      // PC-to-uC string x17
      // (?,11111111,4095)
      vcom_master_out(&Data_string[0]);

输入（PC）-------------------------------输出（微控制器）

“ ???????” -“ ???????”

“（？，* MODE（例如正弦模式），* DAC_VALUE）”-“（S，DAC_VALUE，ADC_VALUE）”

“（？，* MODE（例如正弦模式），* DAC_VALUE）”-“（i，DAC_VALUE，ADC_VALUE）”

“（？，* MODE（例如正弦模式），* DAC_VALUE）”-“（n，DAC_VALUE，ADC_VALUE）”

“（？，* MODE（例如正弦模式），* DAC_VALUE）”-“（e，DAC_VALUE，ADC_VALUE）”   ....   ....

如何停止VCOM设备使用pyserial发送回相同的输入

0 个答案: