Datasheet

27. Analog Comparator (AC)

27.1 Overview

The analog comparator evaluates 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 trigger 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 triggering on comparator output rise, fall or toggle. A block

diagram of the comparator and its surrounding logic is shown below.

The power reduction ADC bit in the Power Reduction Register (PRR.PRADC) must be written to '0' in

order to be able to use the ADC input MUX.

Figure 27-1. Analog Comparator Block Diagram

ACBG

BANDGAP

REFERENCE

ADC MULTIPLEXER

OUTPUT

ACME

ADEN

(1)

AIN0

AIN1

INTERRUPT

SELECT

ACIS1

ACIS0

ACIC

ACIE

ACO

TO T/C1 CAPTURE

TRIGGER MUX

ACI

ANALOG

COMPARATOR

IRQ

ACD

VCC

Note: Refer to the Pin Configuration and the I/O Ports description for Analog Comparator pin placement