Datasheet

272
2549O–AVR–05/12
ATmega640/1280/1281/2560/2561
25.2 Register Description
25.2.1 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
description of this bit, see “Analog Comparator Multiplexed Input” on page 271.
25.2.2 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.
1 0 0 100 ADC4
1 0 0 101 ADC5
1 0 0 110 ADC6
1 0 0 111 ADC7
1 0 1 000 ADC8
1 0 1 001 ADC9
1 0 1 010 ADC10
1 0 1 011 ADC11
1 0 1 100 ADC12
1 0 1 101 ADC13
1 0 1 110 ADC14
1 0 1 111 ADC15
Table 25-1. Analog Comparator Mulitiplexed Input (Continued)
ACME ADEN MUX5 MUX2:0 Analog Comparator Negative Input
Bit 76543210
(0x7B)
– ACME – – MUX5 ADTS2 ADTS1 ADTS0 ADCSRB
Read/Write R R/W RRR/W R/W R/W R/W
Initial Value00000000
Bit 76543210
0x30 (0x50) ACD ACBG ACO ACI ACIE ACIC ACIS1 ACIS0 ACSR
Read/Write R/W R/W RR/W R/W R/W R/W R/W
Initial Value 0 0 N/A00000