ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 134

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

17. Analog Comparator
17.1
134
Analog Comparator Multiplexed Input
Atmel ATtiny24/44/84 [Preliminary]
The analog comparator compares the input values on the positive pin (AIN0) and negative pin
(AIN1). When the voltage on the positive pin (AIN0) is higher than the voltage on the negative
pin (AIN1), the analog comparator output (ACO) is set. The comparator can trigger a separate
interrupt, exclusive to the analog comparator. The user can select Interrupt triggering on com-
parator output rise, fall or toggle. A block diagram of the comparator and its surrounding logic
is shown in
Figure 17-1. Analog Comparator Block Diagram
Notes:
When the analog-to-digital converter (ADC) is configured as a single-ended input channel, it is
possible to select any of the ADC7..0 pins to replace the negative input to the analog compar-
ator. 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 analog comparator, as shown in
17-1. If ACME is cleared or ADEN is set, AIN1 is applied to the negative input of the analog
comparator.
ADC MULTIPLEXER
1. See
2. See
REFERENCE
ACME
ADEN
OUTPUT
BANDGAP
Figure 17-1 on page
(1)
Table 17-1 on page
Figure 1-1 on page 2
ACBG
134.
135.
and
Table 12-9 on page 70
(1)
for Analog Comparator pin placement.
7701E–AVR–02/11
Table