ADMUX (ADC Multiplexer Select Register)
[ REFS1 | REFS0 | ADLAR | MUX4 | MUX3 | MUX2 | MUX1 | MUX0 ]
REF1, 0(Reference selection bit)
ADC 모듈에서 사용하는 기준 전압을 선택하는 비트이다.
00 AREF, internal vref turned off
01 AVCC with external capacitor at AREF pin
10 Reserved
11 Internal 2.56V Voltage reference with external capacitor at AREF pin
ADLAR (ADC Left Adjust Result)
변환 결과가 ADC 데이터 레지스터에 저장될 때 ADC Data Register의 좌측으로 끝을 맞추어 저장된다.
MUX4~0(Analog Channel & Gain Select bit)
ADC 모듈의 아날로그 입력 채널을 선택하는 비트이다.
| MUX4 | sigle ended input | positive differential input | negative differential input | gain |
| 00000 | ADC0 | | | |
| 00001 | ADC1 | | | |
| 00010 | ADC2 | | | |
| 00011 | ADC3 | | | |
| 00100 | ADC4 | | | |
| 00101 | ADC5 | | | |
| 00110 | ADC6 | | | |
| 00111 | ADC7 | | | |
| 01000 | | ADC0 | ADC0 | 10x |
| 01001 | | ADC1 | ADC0 | 10x |
| 01010 | | ADC0 | ADC0 | 200x |
| 01011 | | ADC1 | ADC0 | 200x |
| 01100 | | ADC2 | ADC2 | 10x |
| 01101 | | ADC3 | ADC2 | 10x |
| 01110 | | ADC2 | ADC2 | 200x |
| 01111 | | ADC3 | ADC2 | 200x |
| 10000 | | ADC0 | ADC1 | 1x |
| 10001 | | ADC1 | ADC1 | 1x |
| 10010 | | ADC2 | ADC1 | 1x |
| 10011 | | ADC3 | ADC1 | 1x |
| 10100 | | ADC4 | ADC1 | 1x |
| 10101 | | ADC5 | ADC1 | 1x |
| 10110 | | ADC6 | ADC1 | 1x |
| 10111 | | ADC7 | ADC1 | 1x |
| 11000 | | ADC0 | ADC2 | 1x |
| 11001 | | ADC1 | ADC2 | 1x |
| 11010 | | ADC2 | ADC2 | 1x |
| 11011 | | ADC3 | ADC2 | 1x |
| 11100 | | ADC4 | ADC2 | 1x |
| 11101 | | ADC5 | ADC2 | 1x |
| 11101 | 1.22V(VBG) | | | |
| 11101 | 0V(GND) |