Datasheet

238
2545F–AVR–06/05
ATmega48/88/168
21-2. If ACME is cleared or ADEN is set, AIN1 is applied to the negative input to the Analog
Comparator.
21.1.1 Digital Input Disable Register 1 – DIDR1
• Bit 7..2 – Res: Reserved Bits
These bits are unused bits in the ATmega48/88/168, and will always read as zero.
• Bit 1, 0 – AIN1D, AIN0D: AIN1, AIN0 Digital Input Disable
When this bit is written logic one, the digital input buffer on the AIN1/0 pin is disabled. The corre-
sponding PIN Register bit will always read as zero when this bit is set. When an analog signal is
applied to the AIN1/0 pin and the digital input from this pin is not needed, this bit should be writ-
ten logic one to reduce power consumption in the digital input buffer.
Table 21-2. Analog Comparator Multiplexed Input
ACME ADEN MUX2..0 Analog Comparator Negative Input
0 x xxx AIN1
1 1 xxx AIN1
1 0 000 ADC0
1 0 001 ADC1
1 0 010 ADC2
1 0 011 ADC3
1 0 100 ADC4
1 0 101 ADC5
1 0 110 ADC6
1 0 111 ADC7
Bit 76543210
––––––AIN1DAIN0DDIDR1
Read/Write RRRRRRR/WR/W
Initial Value 00000000