STM32 USB device : First data byte always missing after device initialization and enumeration

Posted on October 25, 2017 at 08:47

Hi,

I am using STM32F401RE. For my USB device application I used DFU class stack from STM32cube mx.

I have ported stack to my application,It is working fine but I always misses first byte received after initialization of USB device and subsequent enumeration.

HAL_PCD_EP_GetRxCount returns correct number bytes but HAL_PCD_EP_Receive gives no data.

Following is code snippet of DATA out stage :

volatile unsigned char rite_14[68];

volatile unsigned int rite_11=0;

USBD_StatusTypeDef USBD_LL_DataOutStage(USBD_HandleTypeDef *pdev , uint8_t epnum, uint8_t *pdata)

{

USBD_EndpointTypeDef *pep;

unsigned int rite_12=0;

if(epnum == 0)

{

pep = &pdev->ep_out[0];

if ( pdev->ep0_state == USBD_EP0_DATA_OUT)

{

if(pep->rem_length > pep->maxpacket)

{

pep->rem_length -= pep->maxpacket;

USBD_CtlContinueRx (pdev,

pdata,

MIN(pep->rem_length ,pep->maxpacket));

}

else

{

if((pdev->pClass->EP0_RxReady != NULL)&&

(pdev->dev_state == USBD_STATE_CONFIGURED))

{

pdev->pClass->EP0_RxReady(pdev);

}

USBD_CtlSendStatus(pdev);

}

}

}

else if((pdev->pClass->DataOut != NULL)&&

(pdev->dev_state == USBD_STATE_CONFIGURED))

{

//pdev->pClass->DataOut(pdev, epnum); not requred

if(epnum == 0x02)

// My application endpoint number

{

rite_11 = HAL_PCD_EP_GetRxCount(pdev->pData, epnum);

rite_12 = HAL_PCD_EP_Receive(pdev->pData, epnum, rite_14, rite_11);

EP2_Handler(rite_14, rite_11);

// appliaction layer processing

}

}

return USBD_OK;

}

#usb-device #stm32_usb_device_library #usb-implementation #usb-fs #usb-stm32f4