The XMEGA analog PORTA is available on the J2 header. This allows the user to connect external signals to the analog-to-digital converter (ADC), digital-to-analog converter (DAC), and analog comparators on PORTA.
The XMEGA digital PORTF and PORTC are available on the J1 and J4 headers, respectively. These ports feature general-purpose I/O and various communication modules (USART, SPI, and TWI). PORTD and PORTF are mixed on the J3 header.
Note
The communication modules on PORTC and PORTF can be interconnected to test various functions and features: The UART can loop back communication with a jumper, or communicate between the two UARTs on the port. The native SPI and the UART in SPI master mode can be connected, and the TWI module can be enabled in both master and slave modes at the same time to get loop-back behavior. (Pull-up resistors can be mounted on R101 and R102. These are not mounted from the factory.)