Defines of pin user labels are found in the file atmel_start_pins.h. These user labels match what is configured in the PINMUX CONFIGURATOR.
For example, PB31 is given a user label DGI_SS, which can be seen as the define associated with this pin in the atmel_start_pins.h file:
#include <hal_gpio.h> #define PA08 GPIO(GPIO_PORTA, 8) #define PA09 GPIO(GPIO_PORTA, 9) #define PA10 GPIO(GPIO_PORTA, 10) #define PA22 GPIO(GPIO_PORTA, 22) #define PA23 GPIO(GPIO_PORTA, 23) #define PB16 GPIO(GPIO_PORTB, 16) #define PB22 GPIO(GPIO_PORTB, 22) #define PB23 GPIO(GPIO_PORTB, 23) #define DGI_SS GPIO(GPIO_PORTB, 31)