① Configure SIUL2's MSCRn register to control the pad state prior to Standby mode entry (for example, writing 0 to SIUL2's MSCRn[OBE], MSCRn[IBE], and MSCR[PUE] fields tristates the corresponding I/O).
② Configure SIUL2's MSCRn[PKE] field as needed for an I/O pad keeping state during Standby mode.
③ Write 0 to DCM's DCMRWF1[STANDBY_IO_CONFIG]. The application core executes WFI, and Standby mode sequence starts.
④ Write 1 to DCM's DCMRWF1[STANDBY_IO_CONFIG] field on Standby mode exit to disable pad keeping. This configures SIUL2 according to its previous settings.
除了上述流程对引脚进行设置，并进入休眠外，还需要在引脚设置中，打开引脚保持使能，也即使能pins->pad keep enable.