Qt Serial Port do not correctly work with USB CDC

[IRBaboon]

Greetings everyone!

The issue I have encountered is - I am trying to establish connection with USB CDC STM Virtual COM port.
I am connecting to virtual com port with standard QSerialPort. If I am translating data to my STM32F103C8 chip with terminal 1.9b - everythings works just fine, I am getting everything I supposed to get. But when I am trying to do the same thing with the help of COM->write, my stm firmware stucks completly. If I try to see the parcel via null modem by connecting my Widget app to terminal1.9b -I see that my parcel from the app is correct.
Anybody help me please :)
Here is the Qt slot for sending:

void MainWindow::getEcho(void)
{
    QByteArray ba_1;
    char len = 0x06;
    char crc = 0;
    char echo = ECHO;
    ba_1.append(SYNCHRO);
    ba_1.append(char(0x00));
    ba_1.append(len);
    ba_1.append(UART_ADDR);
    ba_1.append(echo);
    for(int i = 0; i < ba_1.size(); i++)
    {
        crc ^= ba_1.at(i);
    }
    ba_1.append(crc);
    if(COM->write(ba_1) != -1)
    {
        COM->waitForBytesWritten(200);
        COM->waitForReadyRead(300);
    }
    //ui->echo_button->setEnabled(false);
}

Here is my st cdc receive:

static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
  /* USER CODE BEGIN 6 */
  USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
  USBD_CDC_ReceivePacket(&hUsbDeviceFS);
  HAL_GPIO_TogglePin(PC13_LED_GPIO_Port, PC13_LED_Pin);
  memcpy((USB_RX_MASS + usb_parcel_counter), Buf, *Len);
  usb_parcel_counter++;
  return (USBD_OK);
  /* USER CODE END 6 */
}

[IRBaboon]

At last I have managed to solve this one.
The problem was related (as I expected) to USB CDC receiving bytes from QSerialPort (my Qt term App).
It was my mistake to expect CDC Receive ONE byte by each interrupt as it can obviously receive a number of bytes (*Len).

So what I have done - I made the CDC Receive int handler add a number of received bytes (*Len) to a global var. That totally solved everything.
Here is the code:

/**
  * @brief  Data received over USB OUT endpoint are sent over CDC interface
  *         through this function.
  *
  *         @note
  *         This function will issue a NAK packet on any OUT packet received on
  *         USB endpoint until exiting this function. If you exit this function
  *         before transfer is complete on CDC interface (ie. using DMA controller)
  *         it will result in receiving more data while previous ones are still
  *         not sent.
  *
  * @param  Buf: Buffer of data to be received
  * @param  Len: Number of data received (in bytes)
  * @retval Result of the operation: USBD_OK if all operations are OK else USBD_FAIL
  */
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
  /* USER CODE BEGIN 6 */
  USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
  USBD_CDC_ReceivePacket(&hUsbDeviceFS);
	memcpy((USB_RX_MASS + usb_parcel_counter), Buf, *Len);
	//CDC_Transmit_FS(UserRxBufferFS, 6);
	usb_parcel_counter = usb_parcel_counter + *Len;
  return (USBD_OK);
  /* USER CODE END 6 */
}

Good luck codeMasters!

[JonB]

@IRBaboon said in Qt Serial Port do not correctly work with USB CDC:

if(COM->write(ba_1) != -1)

Although it may not help, you should start by seeing what value this call actually returns, and compare it to the number of bytes you expect to send.

[IRBaboon]

Greetings!
Done it - still no result.
I begin to think that it is due to some QSerialPort authority issues x_x
It looks like the app gets stuck getting bytes from my Qt App via serial port just within CDC_Receive_FS().
I will try to use this https://fpoussin.github.io/doxygen/qtusb/0.7.x/qusbdevice.html
instead of QSerialPort.

[IRBaboon]

At last I have managed to solve this one.
The problem was related (as I expected) to USB CDC receiving bytes from QSerialPort (my Qt term App).
It was my mistake to expect CDC Receive ONE byte by each interrupt as it can obviously receive a number of bytes (*Len).

So what I have done - I made the CDC Receive int handler add a number of received bytes (*Len) to a global var. That totally solved everything.
Here is the code:

/**
  * @brief  Data received over USB OUT endpoint are sent over CDC interface
  *         through this function.
  *
  *         @note
  *         This function will issue a NAK packet on any OUT packet received on
  *         USB endpoint until exiting this function. If you exit this function
  *         before transfer is complete on CDC interface (ie. using DMA controller)
  *         it will result in receiving more data while previous ones are still
  *         not sent.
  *
  * @param  Buf: Buffer of data to be received
  * @param  Len: Number of data received (in bytes)
  * @retval Result of the operation: USBD_OK if all operations are OK else USBD_FAIL
  */
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
  /* USER CODE BEGIN 6 */
  USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
  USBD_CDC_ReceivePacket(&hUsbDeviceFS);
	memcpy((USB_RX_MASS + usb_parcel_counter), Buf, *Len);
	//CDC_Transmit_FS(UserRxBufferFS, 6);
	usb_parcel_counter = usb_parcel_counter + *Len;
  return (USBD_OK);
  /* USER CODE END 6 */
}

Good luck codeMasters!