ADC:
Pin # Signal Name
1 AREF
2 GND
3 ADC0
4 ADC1
5 ADC2
6 ADC3
Some of the Analog to Digital Converter signals are grouped into an
extension.
EXT1:
Pin # Signal Name
1 GND
2 +5V
3 XCK0/AIN0
4 OC3A/AIN1
5 OC3B/INT4
6 OC3C/INT5
7 T3/INT6
8 IC3/INT7
9 SCL/INT0
10 SDA/INT1
11 IC1
12 XCK1
13 T1
14 T2
