Rainbow Electronics Atmega169L - Manual (Page 190)

190
ATmega169V/L
2514A–AVR–08/02
Analog Comparator
Multiplexed Input It is possible to select any of the ADC7..0 pins to replace the negative input to the Ana-
log Comparator. The ADC multiplexer is used to select this input, and consequently, the
ADC must be switched off to utilize this feature. If the Analog Comparator Multiplexer
Enable bit (ACME in ADCSRB) is set and the ADC is switched off (ADEN in ADCSRA is
zero), MUX2..0 in ADMUX select the input pin to replace the negative input to the Ana-
log Comparator, as shown in Table 86. If ACME is cleared or ADEN is set, AIN1 is
applied to the negative input to the Analog Comparator.
Digital Input Disable Register
0 – DIDR0
• 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 corresponding 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 written logic one to reduce power consumption in the digital
input buffer.
Table 86. 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 7 6 5 4 3 2 1 0
– – – – – – AIN1D AIN0D DIDR0
Read/Write R R R R R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0