ST STM32F101xx

RM0008 Low-, medium-, high- and XL-density reset and clock control (RCC)
Doc ID 13902 Rev 12 105/1096
Bit 4 IOPCRST: IO port C reset
Set and cleared by software.
0: No effect
1: Reset IO port C
Bit 3 IOPBRST: IO port B reset
Set and cleared by software.
0: No effect
1: Reset IO port B
Bit 2 IOPARST: IO port A reset
Set and cleared by software.
0: No effect
1: Reset IO port A
Bit 1 Reserved, always read as 0.
Bit 0 AFIORST: Alternate function IO reset
Set and cleared by software.
0: No effect
1: Reset Alternate Function