atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 310

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

24.1
24.1.1
310
Analog Comparator Multiplexed Input
ATmega32U4
Digital Input Disable Register 1 – DIDR1
When changing the ACIS1/ACIS0 bits, the Analog Comparator Interrupt must be disabled 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 ADC13..0 pins to replace the negative input to the Analog Com-
parator. 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
ADCSRB) is set and the ADC is switched off (ADEN in ADCSRA is zero), and MUX2..0 in
ADMUX select the input pin to replace the negative input to the Analog Comparator, as shown in
Table
input to the Analog Comparator.
Table 24-2.
• Bit 0 – AIN0D: AIN0 Digital Input Disable
When this bit is written logic one, the digital input buffer on the AIN0 pin is disabled. The corre-
sponding PIN Register bit will always read as zero when this bit is set. When an analog signal is
applied to the AIN0 pin and the digital input from this pin is not needed, this bit should be written
logic one to reduce power consumption in the digital input buffer.
Bit
Read/Write
Initial Value
ACME
0
1
1
1
1
1
1
1
1
1
24-2. If ACME is cleared or ADEN is set, the Bandgap reference is applied to the negative
ADEN
7
–
R
0
Analog Comparator Multiplexed Input
x
1
0
0
0
0
0
0
0
0
6
–
R
0
MUX2..0
000
001
010
011
100
101
110
xxx
xxx
111
5
–
R
0
Analog Comparator Negative Input
Bandgap Ref.
Bandgap Ref.
ADC0
ADC1
N/A
ADC4
ADC5
ADC6
ADC7
4
–
R
0
3
–
R
0
2
–
R
0
1
–
R
0
0
AIN0D
R/W
0
DIDR1
7766A–AVR–03/08