1、本问题来自CH32V307VCT6 的出厂示例代码，代码的功能是将CH32V307单片机的USB口虚拟成上位机的一个串口。
2、代码在单片机上运行的基本原理是：实现USB接口数据与USART2数据的交叉转发。如上位机给USB接口发送一段数据，USB接口中断程序收到数据后，通过USART2发送出去； 或者，USART2接收到数据后，通过USB接口上传到上位机。
3、经初步理解和调试，上位机通过串口调试程序可以设置虚拟串口的波特率，而该波特率数值同时下传给单片机的USB接口中断程序，中断程序中有一段代码再将此数值设置给单片机的USART2。
4、本提问的目的是寻求对以下终端服务代码的详细解释，要求逐行逐句进行解释和大体框架解释。
```c
void OTG_FS_IRQHandler( void )
{
uint8_t intflag, intst, errflag;
uint16_t len, i;
uint32_t baudrate;
intflag = USBOTG_FS->INT_FG;
intst = USBOTG_FS->INT_ST;
if( intflag & USBFS_UIF_TRANSFER )
{
switch (intst & USBFS_UIS_TOKEN_MASK)
{
/* data-in stage processing */
case USBFS_UIS_TOKEN_IN:
switch ( intst & ( USBFS_UIS_TOKEN_MASK | USBFS_UIS_ENDP_MASK ) )
{
/* end-point 0 data in interrupt */
case USBFS_UIS_TOKEN_IN | DEF_UEP0:
if( USBFS_SetupReqLen == 0 )
{
USBOTG_FS->UEP0_RX_CTRL = USBFS_UEP_R_TOG | USBFS_UEP_R_RES_ACK;
}
if ( ( USBFS_SetupReqType & USB_REQ_TYP_MASK ) != USB_REQ_TYP_STANDARD )
{
/* Non-standard request endpoint 0 Data upload */
}
else
{
/* Standard request endpoint 0 Data upload */
switch( USBFS_SetupReqCode )
{
case USB_GET_DESCRIPTOR:
len = USBFS_SetupReqLen >= DEF_USBD_UEP0_SIZE ? DEF_USBD_UEP0_SIZE : USBFS_SetupReqLen;
memcpy( USBFS_EP0_Buf, pUSBFS_Descr, len );
USBFS_SetupReqLen -= len;
pUSBFS_Descr += len;
USBOTG_FS->UEP0_TX_LEN = len;
USBOTG_FS->UEP0_TX_CTRL ^= USBFS_UEP_T_TOG;
break;
case USB_SET_ADDRESS:
USBOTG_FS->DEV_ADDR = (USBOTG_FS->DEV_ADDR & USBFS_UDA_GP_BIT) | USBFS_DevAddr;
break;
default:
break;
}
}
break;
/* end-point 1 data in interrupt */
case ( USBFS_UIS_TOKEN_IN | DEF_UEP1 ):
USBOTG_FS->UEP1_TX_CTRL ^= USBFS_UEP_T_TOG;
USBOTG_FS->UEP1_TX_CTRL = (USBOTG_FS->UEP1_TX_CTRL & ~USBFS_UEP_T_RES_MASK) | USBFS_UEP_T_RES_NAK;
USBFS_Endp_Busy[ DEF_UEP1 ] = 0;
break;
/* end-point 3 data in interrupt */
case ( USBFS_UIS_TOKEN_IN | DEF_UEP3 ):
USBOTG_FS->UEP3_TX_CTRL ^= USBFS_UEP_T_TOG;
USBOTG_FS->UEP3_TX_CTRL = (USBOTG_FS->UEP3_TX_CTRL & ~USBFS_UEP_T_RES_MASK) | USBFS_UEP_T_RES_NAK;
USBFS_Endp_Busy[ DEF_UEP3 ] = 0;
Uart.USB_Up_IngFlag = 0x00;
break;
/* end-point 4 data in interrupt */
case ( USBFS_UIS_TOKEN_IN | DEF_UEP4 ):
USBOTG_FS->UEP4_TX_CTRL ^= USBFS_UEP_T_TOG;
USBOTG_FS->UEP4_TX_CTRL = (USBOTG_FS->UEP4_TX_CTRL & ~USBFS_UEP_T_RES_MASK) | USBFS_UEP_T_RES_NAK;
USBFS_Endp_Busy[ DEF_UEP4 ] = 0;
break;
default :
break;
}
break;
/* data-out stage processing */
case USBFS_UIS_TOKEN_OUT:
switch ( intst & ( USBFS_UIS_TOKEN_MASK | USBFS_UIS_ENDP_MASK ) )
{
/* end-point 0 data out interrupt */
case USBFS_UIS_TOKEN_OUT | DEF_UEP0:
len = USBOTG_FS->RX_LEN;
if ( intst & USBFS_UIS_TOG_OK )
{
if ( ( USBFS_SetupReqType & USB_REQ_TYP_MASK ) != USB_REQ_TYP_STANDARD )
{
/* Non-standard request end-point 0 Data download */
USBFS_SetupReqLen = 0;
/* Non-standard request end-point 0 Data download */
if( USBFS_SetupReqCode == CDC_SET_LINE_CODING )
{
/* Save relevant parameters such as serial port baud rate */
/* The downlinked data is processed in the endpoint 0 OUT packet, the 7 bytes of the downlink are, in order
4 bytes: baud rate value: lowest baud rate byte, next lowest baud rate byte, next highest baud rate byte, highest baud rate byte.
1 byte: number of stop bits (0: 1 stop bit; 1: 1.5 stop bit; 2: 2 stop bits).
1 byte: number of parity bits (0: None; 1: Odd; 2: Even; 3: Mark; 4: Space).
1 byte: number of data bits (5,6,7,8,16); */
Uart.Com_Cfg[ 0 ] = USBFS_EP0_Buf[ 0 ];
Uart.Com_Cfg[ 1 ] = USBFS_EP0_Buf[ 1 ];
Uart.Com_Cfg[ 2 ] = USBFS_EP0_Buf[ 2 ];
Uart.Com_Cfg[ 3 ] = USBFS_EP0_Buf[ 3 ];
Uart.Com_Cfg[ 4 ] = USBFS_EP0_Buf[ 4 ];
Uart.Com_Cfg[ 5 ] = USBFS_EP0_Buf[ 5 ];
Uart.Com_Cfg[ 6 ] = USBFS_EP0_Buf[ 6 ];
Uart.Com_Cfg[ 7 ] = DEF_UARTx_RX_TIMEOUT;
/* 保存当前串口的波特率 */
baudrate = USBFS_EP0_Buf[ 0 ];
baudrate += ((uint32_t)USBFS_EP0_Buf[ 1 ] << 8 );
baudrate += ((uint32_t)USBFS_EP0_Buf[ 2 ] << 16 );
baudrate += ((uint32_t)USBFS_EP0_Buf[ 3 ] << 24 );
Uart.Com_Cfg[ 7 ] = Uart.Rx_TimeOutMax;
/* 串口初始化操作 */
UART2_USB_Init( );
}
else if( USBFS_SetupReqCode == HID_SET_REPORT )
{
memcpy(&HID_Report_Buffer[Hid_Report_Ptr],USBFS_EP0_Buf,len);
USBFS_SetupReqLen -= len;
Hid_Report_Ptr += len;
USBOTG_FS->UEP0_RX_CTRL ^= USBFS_UEP_R_TOG;
USBOTG_FS->UEP0_RX_CTRL = (USBOTG_FS->UEP0_RX_CTRL & USBFS_UEP_R_RES_MASK) | USBFS_UEP_R_RES_ACK;
}
}
else
{
/* Standard request end-point 0 Data download */
/* Add your code here */
}
if( USBFS_SetupReqLen == 0 )
{
USBOTG_FS->UEP0_TX_LEN = 0;
USBOTG_FS->UEP0_TX_CTRL = USBFS_UEP_T_TOG | USBFS_UEP_T_RES_ACK;
}
}
break;
/* end-point 2 data out interrupt */
case USBFS_UIS_TOKEN_OUT | DEF_UEP2:
USBOTG_FS->UEP2_RX_CTRL ^= USBFS_UEP_R_TOG;
Uart.Tx_PackLen[ Uart.Tx_LoadNum ] = USBOTG_FS->RX_LEN;
Uart.Tx_LoadNum++;
USBOTG_FS->UEP2_DMA = (uint32_t)(uint8_t *)&UART2_Tx_Buf[ ( Uart.Tx_LoadNum * DEF_USB_FS_PACK_LEN ) ];
if( Uart.Tx_LoadNum >= DEF_UARTx_TX_BUF_NUM_MAX )
{
Uart.Tx_LoadNum = 0x00;
USBOTG_FS->UEP2_DMA = (uint32_t)(uint8_t *)&UART2_Tx_Buf[ 0 ];
}
Uart.Tx_RemainNum++;
if( Uart.Tx_RemainNum >= ( DEF_UARTx_TX_BUF_NUM_MAX - 2 ) )
{
USBOTG_FS->UEP2_RX_CTRL &= ~USBFS_UEP_R_RES_MASK;
USBOTG_FS->UEP2_RX_CTRL |= USBFS_UEP_R_RES_NAK;
Uart.USB_Down_StopFlag = 0x01;
}
break;
/* end-point 4 data out interrupt */
case USBFS_UIS_TOKEN_OUT | DEF_UEP4:
USBOTG_FS->UEP4_RX_CTRL ^= USBFS_UEP_R_TOG;
/* Reverse the data and re-upload */
len = USBOTG_FS->RX_LEN;
for( i = 0; i < len; i++ )
{
USBFS_EP4_Buf[ i + 64 ] = ~USBFS_EP4_Buf[ i ];
}
USBOTG_FS->UEP4_TX_LEN = len;
USBOTG_FS->UEP4_TX_CTRL &= ~USBFS_UEP_R_RES_MASK;
USBOTG_FS->UEP4_TX_CTRL |= USBFS_UEP_R_RES_ACK;
break;
default:
break;
}
break;
/* Setup stage processing */
case USBFS_UIS_TOKEN_SETUP:
USBOTG_FS->UEP0_TX_CTRL = USBFS_UEP_T_TOG|USBFS_UEP_T_RES_NAK;
USBOTG_FS->UEP0_RX_CTRL = USBFS_UEP_R_TOG|USBFS_UEP_R_RES_NAK;
/* Store All Setup Values */
USBFS_SetupReqType = pUSBFS_SetupReqPak->bRequestType;
USBFS_SetupReqCode = pUSBFS_SetupReqPak->bRequest;
USBFS_SetupReqLen = pUSBFS_SetupReqPak->wLength;
USBFS_SetupReqValue = pUSBFS_SetupReqPak->wValue;
USBFS_SetupReqIndex = pUSBFS_SetupReqPak->wIndex;
len = 0;
errflag = 0;
if ( ( USBFS_SetupReqType & USB_REQ_TYP_MASK ) != USB_REQ_TYP_STANDARD )
{
/* usb non-standard request processing */
if( USBFS_SetupReqType & USB_REQ_TYP_CLASS )
{
/* Class requests */
switch( USBFS_SetupReqCode )
{
case CDC_GET_LINE_CODING:
pUSBFS_Descr = (uint8_t *)&Uart.Com_Cfg[ 0 ];
len = 7;
break;
case CDC_SET_LINE_CODING:
break;
case CDC_SET_LINE_CTLSTE:
break;
case CDC_SEND_BREAK:
break;
case HID_SET_REPORT: /* 0x09: SET_REPORT */
Hid_Report_Ptr = 0;
break;
case HID_GET_REPORT: /* 0x01: GET_REPORT */
if( USBFS_SetupReqIndex == 0x00 )
{
Hid_Report_Ptr = 0;
len = (USBFS_SetupReqLen >= DEF_USBD_UEP0_SIZE) ? DEF_USBD_UEP0_SIZE : USBFS_SetupReqLen;
memcpy( USBFS_EP0_Buf, &HID_Report_Buffer[Hid_Report_Ptr], len );
Hid_Report_Ptr += len;
}
else
{
errflag = 0xFF;
}
break;
case HID_SET_IDLE: /* 0x0A: SET_IDLE */
if( USBFS_SetupReqIndex == 0x00 )
{
USBFS_HidIdle = (uint8_t)( USBFS_SetupReqValue >> 8 );
}
else
{
errflag = 0xFF;
}
break;
case HID_SET_PROTOCOL: /* 0x0B: SET_PROTOCOL */
if( USBFS_SetupReqIndex == 0x00 )
{
USBFS_HidProtocol = (uint8_t)USBFS_SetupReqValue;
}
else
{
errflag = 0xFF;
}
break;
case HID_GET_IDLE: /* 0x02: GET_IDLE */
if( USBFS_SetupReqIndex == 0x00 )
{
USBFS_EP0_Buf[ 0 ] = USBFS_HidIdle;
len = 1;
}
else
{
errflag = 0xFF;
}
break;
case HID_GET_PROTOCOL: /* 0x03: GET_PROTOCOL */
if( USBFS_SetupReqIndex == 0x00 )
{
USBFS_EP0_Buf[ 0 ] = USBFS_HidProtocol;
len = 1;
}
else
{
errflag = 0xFF;
}
break;
default:
errflag = 0xff;
break;
}
}
else if( USBFS_SetupReqType & USB_REQ_TYP_VENDOR )
{
/* Manufacturer request */
}
else
{
errflag = 0xFF;
}
/* Copy Descriptors to Endp0 DMA buffer */
len = (USBFS_SetupReqLen >= DEF_USBD_UEP0_SIZE) ? DEF_USBD_UEP0_SIZE : USBFS_SetupReqLen;
memcpy( USBFS_EP0_Buf, pUSBFS_Descr, len );
pUSBFS_Descr += len;
}
else
{
/* usb standard request processing */
switch( USBFS_SetupReqCode )
{
/* get device/configuration/string/report/... descriptors */
case USB_GET_DESCRIPTOR:
switch( (uint8_t)( USBFS_SetupReqValue >> 8 ) )
{
/* get usb device descriptor */
case USB_DESCR_TYP_DEVICE:
pUSBFS_Descr = MyDevDescr;
len = DEF_USBD_DEVICE_DESC_LEN;
break;
/* get usb configuration descriptor */
case USB_DESCR_TYP_CONFIG:
pUSBFS_Descr = MyCfgDescr;
len = DEF_USBD_CONFIG_DESC_LEN;
break;
/* get hid report descriptor */
case USB_DESCR_TYP_REPORT:
pUSBFS_Descr = MyHIDReportDesc;
len = DEF_USBD_REPORT_DESC_LEN;
break;
/* get hid descriptor */
case USB_DESCR_TYP_HID:
if( USBFS_SetupReqIndex == 0x02 )
{
pUSBFS_Descr = &MyCfgDescr[ 84 ];
len = 9;
}
else
{
errflag = 0xFF;
}
break;
/* get usb string descriptor */
case USB_DESCR_TYP_STRING:
switch( (uint8_t)( USBFS_SetupReqValue & 0xFF ) )
{
/* Descriptor 0, Language descriptor */
case DEF_STRING_DESC_LANG:
pUSBFS_Descr = MyLangDescr;
len = DEF_USBD_LANG_DESC_LEN;
break;
/* Descriptor 1, Manufacturers String descriptor */
case DEF_STRING_DESC_MANU:
pUSBFS_Descr = MyManuInfo;
len = DEF_USBD_MANU_DESC_LEN;
break;
/* Descriptor 2, Product String descriptor */
case DEF_STRING_DESC_PROD:
pUSBFS_Descr = MyProdInfo;
len = DEF_USBD_PROD_DESC_LEN;
break;
/* Descriptor 3, Serial-number String descriptor */
case DEF_STRING_DESC_SERN:
pUSBFS_Descr = MySerNumInfo;
len = DEF_USBD_SN_DESC_LEN;
break;
default:
errflag = 0xFF;
break;
}
break;
default :
errflag = 0xFF;
break;
}
/* Copy Descriptors to Endp0 DMA buffer */
if( USBFS_SetupReqLen>len )
{
USBFS_SetupReqLen = len;
}
len = (USBFS_SetupReqLen >= DEF_USBD_UEP0_SIZE) ? DEF_USBD_UEP0_SIZE : USBFS_SetupReqLen;
memcpy( USBFS_EP0_Buf, pUSBFS_Descr, len );
pUSBFS_Descr += len;
break;
/* Set usb address */
case USB_SET_ADDRESS:
USBFS_DevAddr = (uint8_t)( USBFS_SetupReqValue & 0xFF );
break;
/* Get usb configuration now set */
case USB_GET_CONFIGURATION:
USBFS_EP0_Buf[0] = USBFS_DevConfig;
if ( USBFS_SetupReqLen > 1 )
{
USBFS_SetupReqLen = 1;
}
break;
/* Set usb configuration to use */
case USB_SET_CONFIGURATION:
USBFS_DevConfig = (uint8_t)( USBFS_SetupReqValue & 0xFF );
USBFS_DevEnumStatus = 0x01;
break;
/* Clear or disable one usb feature */
case USB_CLEAR_FEATURE:
if ( ( USBFS_SetupReqType & USB_REQ_RECIP_MASK ) == USB_REQ_RECIP_DEVICE )
{
/* clear one device feature */
if( (uint8_t)( USBFS_SetupReqValue & 0xFF ) == USB_REQ_FEAT_REMOTE_WAKEUP )
{
/* clear usb sleep status, device not prepare to sleep */
USBFS_DevSleepStatus &= ~0x01;
}
}
else if( ( USBFS_SetupReqType & USB_REQ_RECIP_MASK ) == USB_REQ_RECIP_ENDP )
{
/* Clear End-point Feature */
if( (uint8_t)( USBFS_SetupReqValue & 0xFF ) == USB_REQ_FEAT_ENDP_HALT )
{
switch( (uint8_t)( USBFS_SetupReqIndex & 0xFF ) )
{
case ( DEF_UEP_IN | DEF_UEP1 ):
/* Set End-point 1 IN NAK */
USBOTG_FS->UEP1_TX_CTRL = USBFS_UEP_T_RES_NAK;
break;
case ( DEF_UEP_OUT | DEF_UEP2 ):
/* Set End-point 2 OUT ACK */
USBOTG_FS->UEP2_RX_CTRL = USBFS_UEP_R_RES_ACK;
break;
case ( DEF_UEP_IN | DEF_UEP3 ):
/* Set End-point 3 IN NAK */
USBOTG_FS->UEP3_TX_CTRL = USBFS_UEP_T_RES_NAK;
break;
case ( DEF_UEP_IN | DEF_UEP4 ):
/* Set End-point 4 IN NAK */
USBOTG_FS->UEP4_TX_CTRL = USBFS_UEP_T_RES_NAK;
break;
case ( DEF_UEP_OUT | DEF_UEP4 ):
/* Set End-point 4 OUT ACK */
USBOTG_FS->UEP4_RX_CTRL = USBFS_UEP_R_RES_ACK;
break;
default:
errflag = 0xFF;
break;
}
}
else
{
errflag = 0xFF;
}
}
else
{
errflag = 0xFF;
}
break;
/* set or enable one usb feature */
case USB_SET_FEATURE:
if( ( USBFS_SetupReqType & USB_REQ_RECIP_MASK ) == USB_REQ_RECIP_DEVICE )
{
/* Set Device Feature */
if( (uint8_t)( USBFS_SetupReqValue & 0xFF ) == USB_REQ_FEAT_REMOTE_WAKEUP )
{
if( MyCfgDescr[ 7 ] & 0x20 )
{
/* Set Wake-up flag, device prepare to sleep */
USBFS_DevSleepStatus |= 0x01;
}
else
{
errflag = 0xFF;
}
}
else
{
errflag = 0xFF;
}
}
else if( ( USBFS_SetupReqType & USB_REQ_RECIP_MASK ) == USB_REQ_RECIP_ENDP )
{
/* Set End-point Feature */
if( (uint8_t)( USBFS_SetupReqValue & 0xFF ) == USB_REQ_FEAT_ENDP_HALT )
{
/* Set end-points status stall */
switch( (uint8_t)( USBFS_SetupReqIndex & 0xFF ) )
{
case ( DEF_UEP_IN | DEF_UEP1 ):
/* Set End-point 1 IN STALL */
USBOTG_FS->UEP1_TX_CTRL = ( USBOTG_FS->UEP1_TX_CTRL & ~USBFS_UEP_T_RES_MASK ) | USBFS_UEP_T_RES_STALL;
break;
case ( DEF_UEP_OUT | DEF_UEP2 ):
/* Set End-point 2 OUT STALL */
USBOTG_FS->UEP2_RX_CTRL = ( USBOTG_FS->UEP2_RX_CTRL & ~USBFS_UEP_R_RES_MASK ) | USBFS_UEP_R_RES_STALL;
break;
case ( DEF_UEP_IN | DEF_UEP3 ):
/* Set End-point 3 IN STALL */
USBOTG_FS->UEP3_TX_CTRL = ( USBOTG_FS->UEP3_TX_CTRL & ~USBFS_UEP_T_RES_MASK ) | USBFS_UEP_T_RES_STALL;
break;
case ( DEF_UEP_IN | DEF_UEP4 ):
/* Set End-point 4 IN STALL */
USBOTG_FS->UEP4_TX_CTRL = ( USBOTG_FS->UEP4_TX_CTRL & ~USBFS_UEP_T_RES_MASK ) | USBFS_UEP_T_RES_STALL;
break;
case ( DEF_UEP_OUT | DEF_UEP4 ):
/* Set End-point 4 OUT STALL */
USBOTG_FS->UEP4_RX_CTRL = ( USBOTG_FS->UEP4_RX_CTRL & ~USBFS_UEP_R_RES_MASK ) | USBFS_UEP_R_RES_STALL;
break;
default:
errflag = 0xFF;
break;
}
}
else
{
errflag = 0xFF;
}
}
else
{
errflag = 0xFF;
}
break;
/* This request allows the host to select another setting for the specified interface */
case USB_GET_INTERFACE:
USBFS_EP0_Buf[0] = 0x00;
if ( USBFS_SetupReqLen > 1 )
{
USBFS_SetupReqLen = 1;
}
break;
case USB_SET_INTERFACE:
break;
/* host get status of specified device/interface/end-points */
case USB_GET_STATUS:
USBFS_EP0_Buf[ 0 ] = 0x00;
USBFS_EP0_Buf[ 1 ] = 0x00;
if ( ( USBFS_SetupReqType & USB_REQ_RECIP_MASK ) == USB_REQ_RECIP_DEVICE )
{
if( USBFS_DevSleepStatus & 0x01 )
{
USBFS_EP0_Buf[ 0 ] = 0x02;
}
}
else if( ( USBFS_SetupReqType & USB_REQ_RECIP_MASK ) == USB_REQ_RECIP_ENDP )
{
switch( (uint8_t)( USBFS_SetupReqIndex & 0xFF ) )
{
case ( DEF_UEP_IN | DEF_UEP1 ):
if( ( (USBOTG_FS->UEP1_TX_CTRL) & USBFS_UEP_T_RES_MASK ) == USBFS_UEP_T_RES_STALL )
{
USBFS_EP0_Buf[ 0 ] = 0x01;
}
break;
case ( DEF_UEP_OUT | DEF_UEP2 ):
if( ( (USBOTG_FS->UEP2_RX_CTRL) & USBFS_UEP_R_RES_MASK ) == USBFS_UEP_R_RES_STALL )
{
USBFS_EP0_Buf[ 0 ] = 0x01;
}
break;
case ( DEF_UEP_IN | DEF_UEP3 ):
if( ( (USBOTG_FS->UEP3_TX_CTRL) & USBFS_UEP_T_RES_MASK ) == USBFS_UEP_T_RES_STALL )
{
USBFS_EP0_Buf[ 0 ] = 0x01;
}
break;
case ( DEF_UEP_IN | DEF_UEP4 ):
if( ( (USBOTG_FS->UEP4_TX_CTRL) & USBFS_UEP_T_RES_MASK ) == USBFS_UEP_T_RES_STALL )
{
USBFS_EP0_Buf[ 0 ] = 0x01;
}
break;
case ( DEF_UEP_OUT | DEF_UEP4 ):
if( ( (USBOTG_FS->UEP4_RX_CTRL) & USBFS_UEP_R_RES_MASK ) == USBFS_UEP_R_RES_STALL )
{
USBFS_EP0_Buf[ 0 ] = 0x01;
}
break;
default:
errflag = 0xFF;
break;
}
}
else
{
errflag = 0xFF;
}
if( USBFS_SetupReqLen > 2 )
{
USBFS_SetupReqLen = 2;
}
break;
default:
errflag = 0xFF;
break;
}
}
/* errflag = 0xFF means a request not support or some errors occurred, else correct */
if( errflag == 0xff)
{
/* if one request not support, return stall */
USBOTG_FS->UEP0_TX_CTRL = USBFS_UEP_T_TOG|USBFS_UEP_T_RES_STALL;
USBOTG_FS->UEP0_RX_CTRL = USBFS_UEP_R_TOG|USBFS_UEP_R_RES_STALL;
}
else
{
/* end-point 0 data Tx/Rx */
if( USBFS_SetupReqType & DEF_UEP_IN )
{
/* tx */
len = (USBFS_SetupReqLen>DEF_USBD_UEP0_SIZE) ? DEF_USBD_UEP0_SIZE : USBFS_SetupReqLen;
USBFS_SetupReqLen -= len;
USBOTG_FS->UEP0_TX_LEN = len;
USBOTG_FS->UEP0_TX_CTRL = USBFS_UEP_T_TOG|USBFS_UEP_T_RES_ACK;
}
else
{
/* rx */
if( USBFS_SetupReqLen == 0 )
{
USBOTG_FS->UEP0_TX_LEN = 0;
USBOTG_FS->UEP0_TX_CTRL = USBFS_UEP_T_TOG|USBFS_UEP_T_RES_ACK;
}
else
{
USBOTG_FS->UEP0_RX_CTRL = USBFS_UEP_R_TOG|USBFS_UEP_R_RES_ACK;
}
}
}
break;
/* Sof pack processing */
case USBFS_UIS_TOKEN_SOF:
break;
default :
break;
}
USBOTG_FS->INT_FG = USBFS_UIF_TRANSFER;
}
else if( intflag & USBFS_UIF_BUS_RST )
{
/* usb reset interrupt processing */
USBOTG_FS->DEV_ADDR = 0;
USBFS_Device_Endp_Init( );
UART2_ParaInit( 1 );
USBOTG_FS->INT_FG = USBFS_UIF_BUS_RST;
}
else if( intflag & USBFS_UIF_SUSPEND )
{
/* usb suspend interrupt processing */
if ( USBOTG_FS->MIS_ST & USBFS_UMS_SUSPEND )
{
USBFS_DevSleepStatus |= 0x02;
if( USBFS_DevSleepStatus == 0x03 )
{
/* Handling usb sleep here */
}
}
else
{
USBFS_DevSleepStatus &= ~0x02;
}
USBOTG_FS->INT_FG = USBFS_UIF_SUSPEND;
}
else
{
/* other interrupts */
USBOTG_FS->INT_FG = intflag;
}
}
```
