Posted on November 26, 2014 at 13:16
I have the same problem for STM32F4-Discovery. I generated code using STM32CubeMX, just changed the CDC_Receive_FS and CDC_Transmit_FS functions to be like this:
static
int8_t CDC_Receive_FS (uint8_t* Buf, uint32_t *Len)
{
/* USER CODE BEGIN 7 */
if
(*Len > 0) {
if
(Buf[0] ==
'A'
) {
HAL_GPIO_WritePin(GPIOD, GPIO_PIN_15, GPIO_PIN_SET);
}
else
if
(Buf[0] ==
'B'
) {
HAL_GPIO_WritePin(GPIOD, GPIO_PIN_15, GPIO_PIN_RESET);
}
}
USBD_CDC_ReceivePacket(hUsbDevice_0);
return
(USBD_OK);
/* USER CODE END 7 */
}
uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
{
uint8_t result = USBD_OK;
/* USER CODE BEGIN 8 */
USBD_CDC_SetTxBuffer(hUsbDevice_0, Buf, Len);
result = USBD_CDC_TransmitPacket(hUsbDevice_0);
/* USER CODE END 8 */
return
result;
}
The first time I am using the function, e.g. CDC_Transmit_FS((uint8_t*)''AAA
'', 4), I get USBD_OK and I receive the string in PC, the next time I am trying the send data using the same function I always get USBD_BUSY and don't receive anything in PC while I can send data from PC to the device and receive it inside CDC_Receive_FS function without any problem (I can see it by the toggled leds).
For some reason the USBD_CDC_DataIn function (which is reseting the TxState) is being called by usbd_core only for the first time.
Trying to debug further..
