stsw-stm32121库中：
把数据copy到对应端点的发送缓冲区后，使能发送状态编码STAT_TX=VALID，这时候usb的该端点就可以发送数据了
----->即先调用usb_sil.c中的USB_SIL_Write()，然后调用SetEPRxValid(uint8_t bEpNum)函数。
或者STM32Cube中库文件stm32f1xx_ii_usb.c:中函数USB_WritePMA(),然后调用PCD_SET_EP_TX_STATUS(USBx, ep->num, USB_EP_TX_VALID);函数
/**
* @brief Copy a buffer from user memory area to packet memory area (PMA)
* @param USBx : pointer to USB register.
* @param pbUsrBuf : pointer to user memory area.
* @param wPMABufAddr : address into PMA.
* @param wNBytes : number of bytes to be copied.
* @retval None
*/
void USB_WritePMA(USB_TypeDef *USBx, uint8_t *pbUsrBuf, uint16_t wPMABufAddr, uint16_t wNBytes)
{
uint32_t nbytes = (wNBytes + 1) >> 1; /* nbytes = (wNBytes + 1) / 2 */
uint32_t index = 0, temp1 = 0, temp2 = 0;
uint16_t *pdwVal = NULL;
pdwVal = (uint16_t *)(wPMABufAddr * 2 + (uint32_t)USBx + 0x400);
for (index = nbytes; index != 0; index--)
{
temp1 = (uint16_t) * pbUsrBuf;
pbUsrBuf++;
temp2 = temp1 | (uint16_t) * pbUsrBuf << 8;
*pdwVal++ = temp2;
pdwVal++;
pbUsrBuf++;
}
}
/**
* @brief Copy a buffer from packet memory area (PMA) to user memory area
* @param USBx : pointer to USB register.
* @param pbUsrBuf : pointer to user memory area.
* @param wPMABufAddr : address into PMA.
* @param wNBytes : number of bytes to be copied.
* @retval None
*/
void USB_ReadPMA(USB_TypeDef *USBx, uint8_t *pbUsrBuf, uint16_t wPMABufAddr, uint16_t wNBytes)
{
uint32_t nbytes = (wNBytes + 1) >> 1;/* /2*/
uint32_t index = 0;
uint32_t *pdwVal = NULL;
pdwVal = (uint32_t *)(wPMABufAddr * 2 + (uint32_t)USBx + 0x400);
for (index = nbytes; index != 0; index--)
{
*(uint16_t*)pbUsrBuf++ = *pdwVal++;
pbUsrBuf++;
}
}
stm32cube中定义的端点属性结构体
typedef struct
{
uint8_t num; /*!< Endpoint number
This parameter must be a number between Min_Data = 1 and Max_Data = 15 */
uint8_t is_in; /*!< Endpoint direction
This parameter must be a number between Min_Data = 0 and Max_Data = 1 */
uint8_t is_stall; /*!< Endpoint stall condition
This parameter must be a number between Min_Data = 0 and Max_Data = 1 */
uint8_t type; /*!< Endpoint type
This parameter can be any value of @ref USB_EP_Type */
uint16_t pmaadress; /*!< PMA Address
This parameter can be any value between Min_addr = 0 and Max_addr = 1K */
uint16_t pmaaddr0; /*!< PMA Address0
This parameter can be any value between Min_addr = 0 and Max_addr = 1K */
uint16_t pmaaddr1; /*!< PMA Address1
This parameter can be any value between Min_addr = 0 and Max_addr = 1K */
uint8_t doublebuffer; /*!< Double buffer enable
This parameter can be 0 or 1 */
uint16_t tx_fifo_num; /*!< This parameter is not required by USB Device FS peripheral, it is used
only by USB OTG FS peripheral
This parameter is added to ensure compatibility across USB peripherals */
uint32_t maxpacket; /*!< Endpoint Max packet size
This parameter must be a number between Min_Data = 0 and Max_Data = 64KB */
uint8_t *xfer_buff; /*!< Pointer to transfer buffer */
uint32_t xfer_len; /*!< Current transfer length */
uint32_t xfer_count; /*!< Partial transfer length in case of multi packet transfer */
} USB_EPTypeDef;
F103中usb的最大数据分组为1023个字节（每个端点的PMA最大是1023）
