7. AVR Pin Assignment Table Sorted by Pin

 Port  Pin  Orangutan Function   Notes/Alternate Functions 
B
PB0 LCD control line R/W Timer1 input capture (ICP1)
divided system clock output (CLK0)
PB1 LCD data line DB4 user pushbutton (pressing pulls pin low)
Timer1 PWM output A (OC1A)
PB2 buzzer Timer1 PWM output B (OC1B)
PB3 M2 control line Timer2 PWM output A (OC2A)
ISP programming line
PB4 LCD data line DB5 user pushbutton (pressing pulls pin low)
Caution: also an ISP programming line
PB5 LCD data line DB6 user pushbutton (pressing pulls pin low)
Caution: also an ISP programming line
PB6 20 MHz resonator input not accessable to the user
PB7 20 MHz resonator input not accessable to the user
C
PC0 analog input and digital I/O ADC input channel 0 (ADC0)
PC1 analog input and digital I/O ADC input channel 1 (ADC1)
PC2 analog input and digital I/O ADC input channel 2 (ADC2)
PC3 analog input and digital I/O ADC input channel 3 (ADC3)
PC4 analog input and digital I/O ADC input channel 4 (ADC4)
I2C/TWI input/output data line (SDA)
PC5 analog input and digital I/O ADC input channel 5 (ADC5)
I2C/TWI clock line (SCL)
PC6 RESET pin reset button (pressing resets MCU)
digital I/O disabled by default
D
PD0 digital I/O USART input pin (RXD)
PD1 digital I/O connected to red user LED (high turns LED on)
USART output pin (TXD)
PD2 LCD control line RS external interrupt 0 (INT0)
PD3 M2 control line Timer2 PWM output B (OC2B)
PD4 LCD control line E USART external clock input/output (XCK)
Timer0 external counter (T0)
PD5 M1 control line Timer0 PWM output B (OC0B)
PD6 M1 control line Timer0 PWM output A (OC0A)
PD7 LCD data line DB7 connected to green user LED (high turns LED on)
ADC6

dedicated analog input SMT-jumpered to temperature sensor (LV-168 only)
SMT-jumpered to battery voltage monitor (SV-xx8 only)
ADC input channel 6 (ADC6)
ADC7
dedicated analog input connected to user trimmer potentiometer
ADC input channel 7