2 SERCOM Implementation in SAM D Microcontrollers

Generally, the microcontroller will have separate serial communication modules with different pinouts for each module. Separate dedicated peripherals and user registers will be available for each module. For example, USART will be a separate peripheral with dedicated pins for its function and I²C will be a separate peripheral with its dedicated pins.

In SAM D microcontrollers, all serial peripherals are integrated into a single module, functioning as a serial communication interface (SERCOM). A SERCOM module can be configured as USART, I²C, or SPI selectable by the user. Each SERCOM will be assigned four pads from PAD0 to PAD3. The functionality of each pad is configurable depending on the SERCOM mode used. Unused pads can be used for other purposes and the SERCOM module will not control them unless they are configured to be used by the SERCOM module, for example, SERCOM0 can be configured as USART mode with PAD0 as the transmit pad and PAD1 as the receive pad. Other unused pads (PAD2 and PAD3) can be used as GPIO pins or assigned to some other peripherals. The assignment of SERCOM functionality for different pads is highly flexible, making the SERCOM module more advantageous than the typical serial communication peripheral implementation.