Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F405xx_v2/CAN1/RFI1#0x0
Receive FIFO 1 register
Receive FIFO frame type indication
Receive FIFO identifier type indication
Receive FIFO extended identifier
Receive FIFO standard identifier or receive FIFO extended identifier
https://github.com/cmsis-svd/cmsis-svd-data