Table 20-2. Analog Comparator 0 Negative Input Selection
AC0M2
AC0M1
AC0M0
Description
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
“Vref”/6.40
“Vref”/3.20
“Vref”/2.13
“Vref”/1.60
Bandgap (1.1V)
DAC result
Analog comparator negative input (ACMPM pin)
Reserved
20.4.2 Analog Comparator 1 Control Register – AC1CON
Bit
7
AC1EN
R/W
0
6
AC1IE
R/W
0
5
4
3
2
1
0
AC1IS1 AC1IS0 AC1ICE AC1M2 AC1M1 AC1M0 AC1CON
Read/Write
Initial Value
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
• Bit 7– AC1EN: Analog Comparator 1 Enable Bit
Set this bit to enable the analog comparator 1.
Clear this bit to disable the analog comparator 1.
• Bit 6– AC1IE: Analog Comparator 1 Interrupt Enable bit
Set this bit to enable the analog comparator 1 interrupt.
Clear this bit to disable the analog comparator 1 interrupt.
• Bit 5, 4– AC1IS1, AC1IS0: Analog Comparator 1 Interrupt Select bit
These 2 bits determine the sensitivity of the interrupt trigger.
The different setting are shown in Table 18-7.
Table 20-3. Interrupt Sensitivity Selection
AC1IS1
AC1IS0
Description
0
0
1
1
0
1
0
1
Comparator Interrupt on output toggle
Reserved
Comparator interrupt on output falling edge
Comparator interrupt on output rising edge
• Bit 3– AC1ICE: analog comparator 1 Interrupt Capture Enable bit
Set this bit to enable the input capture of the Timer/Counter1 on the analog comparator event. The comparator output is in
this case directly connected to the input capture front-end logic, making the comparator utilize the noise canceler and edge
select features of the Timer/Counter1 input capture interrupt. To make the comparator trigger the Timer/Counter1 input
capture interrupt, the ICIE1 bit in the timer interrupt mask register (TIMSK1) must be set.
In case ICES1 bit (Section 13.10.2 “Timer/Counter1 Control Register B – TCCR1B” on page 112) is set high, the rising edge
of AC1O is the capture/trigger event of the Timer/Counter1, in case ICES1 is set to zero, it is the falling edge which is taken
into account.
Clear this bit to disable this function. In this case, no connection between the analog comparator and the input capture
function exists.
• Bit 2, 1, 0– AC1M2, AC1M1, AC1M0: analog comparator 1 Multiplexer register
These 3 bits determine the input of the negative input of the analog comparator.
The different setting are shown in Table 20-4 on page 229.
228
ATmega16/32/64/M1/C1 [DATASHEET]
7647O–AVR–01/15
MICROCHIP [ MICROCHIP ]
