ATMEGA323L_14 Datasheet, PDF (126/247 Pages) ATMEL Corporation – Non-volatile Program and Data Memories

Analog Comparator
Multiplexed Input
• Bits 1, 0 – ACIS1, ACIS0: Analog Comparator Interrupt Mode Select
These bits determine which comparator events that trigger the Analog Comparator inter-
rupt. The different settings are shown in Table 42.
Table 42. ACIS1/ACIS0 Settings
ACIS1
ACIS0 Interrupt Mode
0
0
Comparator Interrupt on Output Toggle
0
1
Reserved
1
0
Comparator Interrupt on Falling Output Edge
1
1
Comparator Interrupt on Rising Output Edge
When changing the ACIS1/ACIS0 bits, The Analog Comparator Interrupt must be dis-
abled by clearing its Interrupt Enable bit in the ACSR Register. Otherwise an interrupt
can occur when the bits are changed.
It is possible to select any of the ADC7..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 SFIOR) 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 Ana-
log Comparator, as shown in Table 43. If ACME is cleared (zero) or ADEN is set (one),
PB3 (AIN1) is applied to the negative input to the Analog Comparator.
Table 43. Analog Comparator Multiplexed Input
ACME
ADEN
MUX2..0
Analog Comparator Negative Input
0
x
xxx
AIN1
1
1
xxx
AIN1
1
0
000
ADC0
1
0
001
ADC1
1
0
010
ADC2
1
0
011
ADC3
1
0
100
ADC4
1
0
101
ADC5
1
0
110
ADC6
1
0
111
ADC7
126 ATmega323(L)
1457G–AVR–09/03