If you are not connecting an LCD to the board’s LCD connector, then pin 11 (PB7) and pin 4 (A6/PD4) are free. Both pins can be used for digital input and output. In addition, pin 11 can be used as a PWM output and a pin change interrupt and pin 4 can be used as an analog input. | If you are not connecting an LCD to the board’s LCD connector, then pin 11 (PB7) and pin 4 (A6/PD4) are free. Both pins can be used for digital input and output. In addition, pin 11 can be used as a PWM output and a pin change interrupt and pin 4 can be used as an analog input. |