4.8 Backup I/O Pins
These pins can be used when operating in Backup mode and are not mapped to the normal PORT functions, hence these pins are controlled by the related peripheral registers.
| Peripheral | Signal | I/O Pin |
|---|---|---|
| XOSC32K | XIN32 | PA00 |
| XOSC32K | XOUT32 | PA01 |
| RTC | IN0 | PB00 |
| SUPC (or RTC) | OUT0 (or OUT) | PB01 |
| SUPC (or RTC) | OUT1 (or IN1) | PB02 |
| SUPC | VBAT | PB03 |
| RTC | IN3 | PC00 |
| RTC | IN4 | PC01 |
Important: These I/Os have specific electrical characteristics. Refer to I/O Pin Electrical
Specifications.