ATmega169P
20. AC - Analog Comparator
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 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 com-
parator output rise, fall or toggle. A block diagram of the comparator and its surrounding logic is
shown in Figure 20-1.
The Power Reduction ADC bit, PRADC, in ”PRR – Power Reduction Register” on page 44 must
be disabled by writing a logical zero to be able to use the ADC input MUX.
Figure 20-1. Analog Comparator Block Diagram(2)
BANDGAP
REFERENCE
ACBG
ACME
ADEN
ADC MULTIPLEXER
OUTPUT(1)
Notes: 1. See Table 20-1 on page 212.
2. Refer to Figure 1-1 on page 2 and Table 12-5 on page 74 for Analog Comparator pin
placement.
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8018A–AVR–03/06
ATMEL [ ATMEL ]
