Analog Comparator; Adc Control And Status Register B - Adcsrb; Analog Comparator Control And Status Register - Acsr - Atmel ATtiny25 Manual

17. Analog Comparator

17.1 ADC Control and Status Register B – ADCSRB
17.2 Analog Comparator Control and Status Register – ACSR
ATtiny25/45/85
108
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 inter-
rupt, 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
in Figure 17-1.
Figure 17-1. Analog Comparator Block Diagram
BANDGAP
REFERENCE
ACBG
ACME
ADEN
ADC MULTIPLEXER
(1)
OUTPUT
Notes: 1. See Table 17-2 on page
2. Refer to Figure 1-1 on page 2
placement.
Bit 7
BIN
Read/Write R
Initial Value 0
• Bit 6 – ACME: Analog Comparator Multiplexer Enable
When this bit is written logic one and the ADC is switched off (ADEN in ADCSRA is zero), the
ADC multiplexer selects the negative input to the Analog Comparator. When this bit is written
logic zero, AIN1 is applied to the negative input of the Analog Comparator. For a detailed
description of this bit, see
Bit 7
ACD
Read/Write R/W
Initial Value 0
• Bit 7 – ACD: Analog Comparator Disable
When this bit is written logic one, the power to the Analog Comparator is switched off. This bit
can be set at any time to turn off the Analog Comparator.
110.
and Table 10-5 on page 57
6 5 4
ACME IPR –
R/W R R
0 0 0
"Analog Comparator Multiplexed Input" on page
6 5 4
ACBG ACO ACI
R/W R R/W
0 N/A 0
(2)
for Analog Comparator pin
3 2 1
– ADTS2 ADTS1
R R/W R/W
0 0 0
3 2 1
ACIE – ACIS1
R/W R R/W
0 0 0
0
ADTS0 ADCSRB
R/W
0
110.
0
ACIS0 ACSR
R/W
0
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