Datasheet

78
ATtiny13
2535E–AVR–10/04
Analog Comparator
Multiplexed Input
It is possible to select any of the ADC3..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), MUX1..0 in ADMUX select the input pin to replace the negative input to the Ana-
log Comparator, as shown in Table 35. 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
• Bits 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 35. Analog Comparator Multiplexed Input
ACME ADEN MUX1..0 Analog Comparator Negative Input
0x xxAIN1
11 xxAIN1
10 00ADC0
10 01ADC1
10 10ADC2
10 11ADC3
Bit 76543210
– – ADC0D ADC2D ADC3D ADC1D AIN1D AIN0D DIDR0
Read/Write R R R/W R/W R/W R/W R/W R/W
Initial Value00000000