The SCL and SDA signals are mapped to physical pins using the PSEL.SCL and PSEL.SDA registers.
These registers and their configurations are only used when TWIM is enabled, and retained while the device is in System ON mode. When the peripheral is disabled, the pins behave as regular GPIOs and are configured according to their respective OUT bit field and PIN_CNF[n] register. Configure registers PSEL.SCL and PSEL.SDA when TWIM is disabled.
Only one peripheral can be assigned to drive a GPIO pin at a time. If more than one peripheral is assigned to a GPIO pin, it could result in unpredictable behavior.
When TWIM is in System OFF mode or disabled, the pins using TWIM must be configured by the GPIO peripheral according to the following table to ensure correct pin behavior.
| TWIM signal | TWIM pin | Drive strength | Direction | Output value |
|---|---|---|---|---|
| SCL | As specified in PSEL.SCL | S0D1 | Input | Not applicable |
| SDA | As specified in PSEL.SDA | S0D1 | Input | Not applicable |