USB CDC device conflict with other peripheral

[ABricout]

Hello,

I am working on the STM32H7A3ZGT6 with the following parameters

• CubeIDE 1.13.0
• CubeMX 6.9.0

I am trying to add a USB device CDC for debugging. My objective is to print debug data on the virtual port com. I am sucessufull at sending data directly after the USB CDC init but when I use another module, the USB isn't working anymore and the TX function if returning a Busy error

I configured the USB with the following parameters: (Clock to USB = 48MHz)

The USB is initialized fine and I can open the Port Com on my computer.

If I put data to the usb directly after the USB init it is working, but once I use another peripheral (UART, SPI…) the USB no longer outputs any data and the function CDC_Transmit_HS returns a busy error

  MX_OCTOSPI2_Init();
  MX_USB_DEVICE_Init();  // INIT USB OK
  /* USER CODE BEGIN 2 */
  HAL_Delay(5000);
  uint8_t test_cdc_usb[] = "Coucou";
  print_debug_usb(test_cdc_usb, sizeof(test_cdc_usb)); // PUT USB DATA OK
  print_debug_usb(test_cdc_usb, sizeof(test_cdc_usb)); // PUT USB DATA OK
  /*Memory*/
  memory_SPI_Init(); // USES OCTOSPI2
  memoryMes_init();  // USES OCTOSPI2
  print_debug_usb(test_cdc_usb, sizeof(test_cdc_usb));  // PUT USB DATA ERROR BUSY

The Function used to flush data to the USB CDC is the following:

uint8_t usb_cdc_debug_buffer[2048];
void print_debug_usb(uint8_t * data, uint16_t size)
{
	memcpy(usb_cdc_debug_buffer, data, size);
	usb_cdc_debug_buffer[size] = '\n';
	while(CDC_Transmit_HS(usb_cdc_debug_buffer, (size+1)) == USBD_BUSY);
	HAL_Delay(300);
}

I didn't change the code genereated by CubeMX for the USB device and am using the CDC_Transmit_HS found in the usbd_cdc_if.h file.

Do you have any idea where this could come from?

thank you

Augustin

[AScha.3]

How did you set the interrupts priority?

Usb working fine with high priority, just system and systick should be higher, all other lower.

[ABricout]

Hello,

The priority settings does not change the problem. I put the usb as highest after the system and I still have the same behavior

[gbm]

DCC_Transmit_FS() must be called from an interrupt service routine of the same priority as USB interrupt If you call it from main, it will sooner or later hang.

[ABricout]

Ok, so I created a timer with the same interrupt priority and I call the function CDC_TRANSMIT_HS in the handler of this timer.

The result is still the same, when I use another peripheral I get a busy error from the CDC_TRANSMIT_HS

#include "usbd_cdc_if.h"
#include "tim.h"

uint8_t usb_cdc_debug_buffer[2048];
uint16_t usb_cdc_data_size;
void USB_handler(void)
{
	HAL_TIM_Base_Stop_IT(&htim17); // Time timer
	CDC_Transmit_HS((uint8_t*)usb_cdc_debug_buffer, usb_cdc_data_size);
}

void print_debug_usb(char * data, uint16_t size)
{
	memcpy(usb_cdc_debug_buffer, data, size);
	usb_cdc_debug_buffer[size] = '\r';
	usb_cdc_debug_buffer[size+1] = '\n';
	usb_cdc_data_size = size+2;
	HAL_TIM_Base_Start_IT(&htim17); // Time timer

	HAL_Delay(300);
}

[ABricout]

I also tried to put an echo in the USB received function (sure to have the same IT priority) to send the data received back. I got the same result BUSY:

static int8_t CDC_Receive_HS(uint8_t* Buf, uint32_t *Len)
{
  /* USER CODE BEGIN 11 */
  USBD_CDC_SetRxBuffer(&hUsbDeviceHS, &Buf[0]);
  USBD_CDC_ReceivePacket(&hUsbDeviceHS);
  uint16_t len = *Len;
  CDC_Transmit_HS (Buf, len);
  return (USBD_OK);
  /* USER CODE END 11 */
}