Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F415xx_v2/CAN1/ESTS#0x0
Error status register
Error active flag
Error passive flag
Bus-off flag
Error type record
Transmit error counter
Receive error counter
https://github.com/cmsis-svd/cmsis-svd-data