ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 244

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

23. Analog Comparator
23.1
23.2
244
Overview
Analog Comparator Multiplexed Input
Atmel ATmega48PA/88PA/168PA [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’s output can be set to trig-
ger the Timer/Counter1 Input Capture function. In addition, the comparator can trigger a
separate interrupt, exclusive to the Analog Comparator. The user can select Interrupt trigger-
ing on comparator output rise, fall or toggle. A block diagram of the comparator and its
surrounding logic is shown in
The Power Reduction ADC bit, PRADC, in
be disabled by writing a logical zero to be able to use the ADC input MUX.
Figure 23-1. Analog Comparator Block Diagram
Notes:
It is possible to select any of the ADC7...0 pins to replace the negative input to the Analog
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 Analog Comparator, as
shown in
to the Analog Comparator
ADC MULTIPLEXER
REFERENCE
ACME
ADEN
OUTPUT
BANDGAP
1. See
2. Refer to
Table
placement.
(1)
ACBG
Table 23-1 on page
23-1. If ACME is cleared or ADEN is set, AIN1 is applied to the negative input
Figure 1-1 on page 2
Figure
245.
23-1.
and
Table 14-9 on page 88
“Minimizing Power Consumption” on page 42
(2)
for Analog Comparator pin
9223B–AVR–09/11
must