Analysis of STM32 usb_mem.c and usb_sil.c files

/******************************************************************************* * Function Name : UserToPMABufferCopy * Description : Copy data from the user memory area to PMA (data packet memory area) * Input : pbUsrBuf: points to the user's memory area * wPMABufAddr: the address of wPMABufAddr to be copied to PMA * wNBytes: the length of the data to be copied (unit: word) * Output : None. * Return : None . *******************************************************************************/ void UserToPMABufferCopy(uint8_t *pbUsrBuf, uint16_t wPMABufAddr, uint16_t wNBytes) { uint32_t n = (wNBytes + 1) >> 1; //n = (wNBytes + 1) / 2, indicating how many words uint32_t i, temp1, temp2; uint16_t *pdwVal; pdwVal = (uint16_t *)(wPMABufAddr * 2 + PMAAddr); //pdwVal stores the address where the data is to be stored for (i = n; i != 0; i--) //Start testing the data { temp1 = (uint16_t) * pbUsrBuf; pbUsrBuf++; temp2 = temp1 | (uint16_t) * pbUsrBuf << 8; //Integrate 2 16-bit data *pdwVal++ = temp2; //Copy the integrated data to PMA pdwVal++; //The destination pointer points to the next address pbUsrBuf++; //The source pointer points to the next address } } /******************************************************************************* * Function Name : PMAToUserBufferCopy * Description : Copy a buffer from user memory area to packet memory area (PMA) * Input : pbUsrBuf points to the user's memory area * wPMABufAddr PAM address * wNBytes number of bytes to be copied * Output : None. * Return : None. ******************************************************************************/ void PMAToUserBufferCopy(uint8_t *pbUsrBuf, uint16_t wPMABufAddr, uint16_t wNBytes) { uint32_t n = (wNBytes + 1) >> 1; //n = (wNBytes + 1) / 2, indicating how many words uint32_t i; uint32_t *pdwVal; pdwVal = (uint32_t *)(wPMABufAddr * 2 + PMAAddr); //Read 1 word of data from the PAM area for (i = n; i != 0; i--) { *(uint16_t*)pbUsrBuf++ = *pdwVal++; //Copy the user's memory area pbUsrBuf++; } }

/*******************************************************************************
* Function Name : USB_SIL_Init
* Description : Initialize USB device IP and endpoints
* Input : None.
* Output : None.
* Return : Status.
*******************************************************************************/
uint32_t USB_SIL_Init(void)
{
#ifndef STM32F10X_CL

/* USB interrupts initialization */
/* clear pending interrupts */
_SetISTR(0); //Disable all interrupts
wInterrupt_Mask = IMR_MSK;
/* set interrupts mask */
_SetCNTR(wInterrupt_Mask); //Enable some interrupts

#else

/* Perform OTG Device initialization procedure (including EP0 init) */
OTG_DEV_Init(); //Execute initialization procedure OTG device (including EP0 initialization)

#endif /* STM32F10X_CL */

return 0;
}

/*******************************************************************************
* Function Name : USB_SIL_Write
* Description : Write data to the selected endpoint
* Input : bEpAddr: address of non-control endpoint
* pBufferPointer: points to the buffer data to be written to the endpoint
* wBufferSize: length of data to be written (unit: byte)
* Output : None.
* Return : Status.
*******************************************************************************/
uint32_t USB_SIL_Write(uint8_t bEpAddr, uint8_t* pBufferPointer, uint32_t wBufferSize)
{
#ifndef STM32F10X_CL

UserToPMABufferCopy(pBufferPointer, GetEPTxAddr(bEpAddr & 0x7F), wBufferSize); //Copy user data to PMA

SetEPTxCount((bEpAddr & 0x7F), wBufferSize); //Update the control register of data length

#else

PCD_EP_Write (bEpAddr, pBufferPointer, wBufferSize); //Use the PCD interface layer function to write to the selected endpoint

#endif /* STM32F10X_CL */

return 0;
}

/*******************************************************************************
* Function Name : USB_SIL_Read
* Description : Read data from the selected endpoint
* Input : bEpAddr: address of non-control endpoint
* pBufferPointer: point to the address of the data area to be saved
* Output : None.
* Return : Return the length of the read data (unit: byte)
*******************************************************************************/
uint32_t USB_SIL_Read(uint8_t bEpAddr, uint8_t* pBufferPointer)
{
uint32_t DataLength = 0;

#ifndef STM32F10X_CL

DataLength = GetEPRxCount(bEpAddr & 0x7F); //Get the received data length from the selected endpointPMAToUserBufferCopy

(pBufferPointer, GetEPRxAddr(bEpAddr & 0x7F), DataLength); //Copy data from PMA to user area

#else

USB_OTG_EP *ep;

ep = PCD_GetOutEP(bEpAddr); //Get the structure pointer of the selected endpointDataLength

= ep->xfer_len; //Get the received data lengthPCD_EP_Read

(bEpAddr, pBufferPointer, DataLength); //Use PCD interface layer function to read the selected port

#endif /* STM32F10X_CL */

return DataLength; //Return the received data length
}