GigaDevice Semiconductor GD32 Series, User Manual

Page: 25 / 65

AN050
GD32 USBFS&USBHS Firmware Library User Guide
25
In interrupt handler function of IN endpoint, process transfer finished interrupt and transmit
FIFO empty interrupt. After corresponding IN endpoint interrupt event generated, MCU
execute the corresponding interrupt handler function through polling interrupt flag.
The interrupt handler function of Rx FIFO non empty is shown as below:
static uint32_t usbd_int_rxfifo ( usb_core_driver * udev )
{
usb_transc * transc = NULL ;
uint8_t data_PID = 0U ;
uint32_t bcount = 0U ;
__IO uint32_t devrxstat = 0U ;
/* disable the Rx status queue non-empty interrupt */
udev -> regs . gr -> GINTEN &= ~ GINTEN_RXFNEIE ;
/* get the status from the top of the FIFO */
devrxstat = udev -> regs . gr -> GRSTATP ;
uint8_t ep_num = ( uint8_t )( devrxstat & GRSTATRP_EPNUM );
transc = & udev -> dev . transc_out [ ep_num ];
bcount = ( devrxstat & GRSTATRP_BCOUNT ) >> 4U ;
data_PID = ( uint8_t )(( devrxstat & GRSTATRP_DPID ) >> 15U );
switch (( devrxstat & GRSTATRP_RPCKST ) >> 17U ) {
case RSTAT_GOUT_NAK :
break ;
case RSTAT_DATA_UPDT :
if ( bcount > 0U ) {
( void ) usb_rxfifo_read (& udev -> regs , transc -> xfer_buf , ( uint16_t ) bcount ); // read
FIFO
transc -> xfer_buf += bcount ;
transc -> xfer_count += bcount ;
}
break ;
case RSTAT_XFER_COMP :
/* trigger the OUT endpoint interrupt */
break ;