PCB (that has STM32F407 as MCU and USB CDC interface is running without error) is not recognized by PC( windows 10).

[risingEdge]

The STM32F407 is programmed with STMCube IDE and there is no error during initizalition of the functions; HAL_Init(), SystemClock_Init(); MX_USB_DEVICE_Init().

As I expect that virtual com port will be opened while the PCB is plugged into my PC, unfortunately it didnot happen.

What should I do?

[waclawek.jan]

Which OTG? If FS, DFU works? The same (presumably minimal) firmware works on a "known good" board such as Nucleo/Disco/Eval?

JW

[risingEdge]

Sorry for incomplete information. USB OTG HS. But actually I didnt use any Nucleo/Disco/Eval, I am using designed PCB

[risingEdge]

When the problem is localized, the transmit function of "CDC_Transmit_HS" returnes with "return USBD_BUSY".

uint8_t CDC_Transmit_HS(uint8_t* Buf, uint16_t Len)

{

uint8_t result = USBD_OK;

/* USER CODE BEGIN 12 */

USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)hUsbDeviceHS.pClassData;

if (hcdc->TxState != 0){

return USBD_BUSY;

}

But, I want to say that the windows PC doesnot recognize the STM MCU ( no Virtual ComPort )