Nucleo-L4R5ZI USB CDC

[mike]

Dear All,

I would like to ask how to manage USB CDC on the nucleo-l4r5zi board. I would like to send data from a uC to the PC via USB.

The main function looks like that:

int main(void)

{

 HAL_Init();

 SystemClock_Config();

 MX_GPIO_Init();

 MX_USB_DEVICE_Init();

 uint8_t myBuf[] = "Hello World \r\n";

 uint8_t stat;

 while (1)

 {

    stat = CDC_Transmit_FS(myBuf, 12);

    if(stat!=USBD_OK)

    HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_7);

    HAL_Delay(500);

    HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_14);

 }

}

The main problem is inside the function CDC_Transmit_FS(...), in line:

if (hcdc->TxState != 0)

 {

   return USBD_BUSY;

 }

I do not know how to make the TxState 0.

I also removed SB193 and 195 from the board as it states in the ref manual of the board.

[Moritz Diller]

Hi Mike,

I also had some trouble with USB CDC in the last few weeks on an STM32L433CC.

1) Modify MX_USB_DEVICE_Init(...) to wait until the USB connection is established

#define USB_DEVICE_CONNECTION_TIMEOUT_MS	2000
	...
	/* USER CODE BEGIN USB_DEVICE_Init_PostTreatment */
	uint32_t tickstart_ms = HAL_GetTick();
	while(hUsbDeviceFS.dev_state != USBD_STATE_CONFIGURED){
		// wait until USB state is configured or timeout is reached
		if ((HAL_GetTick() - tickstart_ms) > USB_DEVICE_CONNECTION_TIMEOUT_MS) {
			break;
		}
	}
}
/* USER CODE END USB_DEVICE_Init_PostTreatment */

2) Update the HAL library to the latest version

https://community.st.com/s/question/0D50X00009ZDBaESAX/usb-stall-behavior-cubemx-cdc

Did your PC recognize the device correctly as a Virtual COM Port or is any error shown in the device manager?

Kind regards,

Moritz