configure RTC PAD20
FUN_IE | input enable in work mode |
SLP_OE | output enable in sleep mode |
SLP_IE | input enable in sleep mode |
SLP_SEL | 1: enable sleep mode during sleep,0: no sleep mode |
FUN_SEL | function sel |
MUX_SEL | 1: use RTC GPIO,0: use digital GPIO |
RUE | RUE |
RDE | RDE |
DRV | DRV |