ATMEGA8_08 Datasheet, PDF (206/308 Pages) ATMEL Corporation – 8-bit with 8K Bytes In-System Programmable Flash

Table 74. Voltage Reference Selections for ADC
REFS1 REFS0 Voltage Reference Selection
0
1
AV_CC with external capacitor at AREF pin
1
0
Reserved
1
1
Internal 2.56V Voltage Reference with external capacitor at AREF pin
• Bit 5 – ADLAR: ADC Left Adjust Result
The ADLAR bit affects the presentation of the ADC conversion result in the ADC Data Register.
Write one to ADLAR to left adjust the result. Otherwise, the result is right adjusted. Changing the
ADLAR bit will affect the ADC Data Register immediately, regardless of any ongoing conver-
sions. For a complete description of this bit, see “The ADC Data Register – ADCL and ADCH” on
page 208.
• Bits 3:0 – MUX3:0: Analog Channel Selection Bits
The value of these bits selects which analog inputs are connected to the ADC. See Table 75 for
details. If these bits are changed during a conversion, the change will not go in effect until this
conversion is complete (ADIF in ADCSRA is set).
Table 75. Input Channel Selections
MUX3..0
Single Ended Input
0000
ADC0
0001
ADC1
0010
ADC2
0011
ADC3
0100
ADC4
0101
ADC5
0110
ADC6
0111
ADC7
1000
1001
1010
1011
1100
1101
1110
1111
1.30V (V_BG)
0V (GND)
206 ATmega8(L)
2486T–AVR–05/08