
179
4378C–AVR–09/08
AT90PWM1
These 2 bits determine the sensitivity of the interrupt trigger.
Bit 2, 1, 0– AC2M2, AC2M1, AC2M0: Analog Comparator 2 Multiplexer register
These 3 bits determine the input of the negative input of the analog comparator.
18.2.3
Analog Comparator Status Register – ACSR
Bit 7– ACCKDIV: Analog Comparator Clock Divider
The analog comparators can work with a clock up to 8MHz@3V and 16MHz@5V.
Set this bit in case the clock frequency of the microcontroller is higher than 8 MHz to insert a
divider by 2 between the clock of the microcontroller and the clock of the analog comparators.
Clear this bit to have the same clock frequency for the microcontroller and the analog
comparators.
Bit 6– AC2IF: Analog Comparator 2 Interrupt Flag Bit
This bit is set by hardware when comparator 2 output event triggers off the interrupt mode
defined by AC2IS1 and AC2IS0 bits in AC2CON register.
This bit is cleared by hardware when the corresponding interrupt vector is executed in case the
AC2IE in AC2CON register is set. Anyway, this bit is cleared by writing a logical one on it.
This bit can also be used to synchronize ADC or DAC conversions.
Bit 5– AC0IF: Analog Comparator 0 Interrupt Flag Bit
This bit is set by hardware when comparator 0 output event triggers off the interrupt mode
defined by AC0IS1 and AC0IS0 bits in AC0CON register.
Table 58. Interrupt sensitivity selection
AC2IS1
AC2IS0
Description
0
Comparator Interrupt on output toggle
0
1
Reserved
1
0
Comparator interrupt on output falling edge
1
Comparator interrupt on output rising edge
Table 59. Analog Comparator 2 negative input selection
AC2M2
AC2M1
AC2M0
Description
000“Vref”/6.40
001“Vref”/3.20
010“Vref”/2.13
011“Vref”/1.60
100Analog Comparator Negative Input (ACMPM pin)
101DAC result
110Reserved
111Reserved
Bit
7
6
4
3
2
0
ACCKDIV
AC2IF
AC0IF
-
AC2O
AC0O
ACSR
Read/Write
R/W
-
R
Initial Value
0