User LEDs
Four yellow LEDs are connected to the PORTB on PB[7:4]. The LEDs are active low and thus lights up when the respective lines are output low by the ATxmega128B1
Power LED
The green LED, mounted near the PDI connector and labeled “POWER”, indicates if the output voltage that is generated by the regulator is present. It is connected to PORTE on PE4. By default, this LED is powered and will switch off when PE4 = 0