atmega163l ATMEL Corporation, atmega163l Datasheet - Page 102

• Manufacturer Part Number: atmega163l
• Description: Atmega163 8-bit Avr Microcontroller With 16k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

The Analog
Comparator
The Analog Comparator
Control And Status Register –
ACSR
102
ATmega163(L)
The Analog Comparator compares the input values on the positive pin PB2 (AIN0) and
negative pin PB3 (AIN1). When the voltage on the positive pin PB2 (AIN0) is higher than
the voltage on the negative pin PB3 (AIN1), the Analog Comparator Output, ACO, is set
(one). The comparator’s output can be set to trigger the Timer/Counter1 Input Capture
function. In addition, the comparator can trigger a separate interrupt, 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 56.
Figure 56. Analog Comparator Block Diagram
Note:
• Bit 7 – ACD: Analog Comparator Disable
When this bit is set(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 con-
sumption 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 and the BOD is enabled (BODEN Fuse is programmed), a fixed
bandgap voltage of nominally 1.22V replaces the positive input to the Analog Compara-
tor. When this bit is cleared, AIN0 is applied to the positive input of the Analog
Comparator.
Bit
$08 ($28)
Read/Write
Initial Value
ADC MULTIPLEXER
ACME
ADEN
REFERENCE
BANDGAP
OUTPUT
1. See Figure 57 on page 106.
ACD
R/W
ACBG
1)
7
0
ACBG
R/W
6
0
ACO
N/A
5
R
R/W
ACI
4
0
ACIE
R/W
3
0
ACIC
R/W
2
0
ACIS1
R/W
1
0
ACIS0
R/W
0
0
1142E–AVR–02/03
ACSR