o read/write the AFIO_EVCR, AFIO_MAPR and AFIO_EXTICRX registers, the AFIO clock should first be enabled. Refer to Section 7.3.7: APB2 peripheral clock enable register (RCC_APB2ENR).
AFIO_MAPR
External interruption EXI
o read/write the AFIO_EVCR, AFIO_MAPR and AFIO_EXTICRX registers, the AFIO clock should first be enabled. Refer to Section 7.3.7: APB2 peripheral clock enable register (RCC_APB2ENR).