
162
8008H–AVR–04/11
ATtiny48/88
16.2
Register Description
16.2.1
ADCSRB – ADC Control and Status Register B
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
16.2.2
ACSR – Analog Comparator Control and Status Register
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. This will reduce power consumption in
Active and Idle mode. When changing the ACD bit, the Analog Comparator Interrupt must be
disabled by clearing the ACIE bit in ACSR. Otherwise an interrupt can occur when the bit is
changed.
Bit 6 – ACBG: Analog Comparator Bandgap Select
When this bit is set, a fixed internal bandgap reference voltage replaces the positive input to the
Analog Comparator. When this bit is cleared, AIN0 is applied to the positive input of the Analog
Bit 5 – ACO: Analog Comparator Output
The output of the Analog Comparator is synchronized and then directly connected to ACO. The
synchronization introduces a delay of 1 – 2 clock cycles.
1
0
010
ADC2
1
0
011
ADC3
1
0
100
ADC4
1
0
101
ADC5
1
0
110
ADC6
1
0
111
ADC7
Table 16-1.
Analog Comparator Multiplexed Input (Continued)
ACME
ADEN
MUX[2:0]
Analog Comparator Negative Input
Bit
7
65432
10
–ACME
–
ADTS2
ADTS1
ADTS0
ADCSRB
Read/Write
R
R/W
R
R/W
Initial Value
0
00000
00
Bit
7
654
32
10
ACD
ACBG
ACO
ACI
ACIE
ACIC
ACIS1
ACIS0
ACSR
Read/Write
R/W
R
R/W
Initial Value
0
N/A
0