Rainbow Electronics ATmega64M1 - Manual (Page 262)

262
8209A–AVR–08/09
ATmega16M1/32M1/64M1
.
• Bit 3 – Res: Reserved
This bit isreserved and will always read as zero.
• Bit 2:0– AC3M[2:0]: Analog Comparator 3 Multiplexer register
These 3 bits determine the input of the negative input of the analog comparator.
The different setting are shown in
Table 24-6 .
24.4.5 ACSR – Analog Comparator Status Register
• Bit 7 – AC3IF: Analog Comparator 3 Interrupt Flag Bit
This bit is set by hardware when comparator 3 output event triggers off the interrupt mode
defined by AC3IS1 and AC3IS0 bits in AC2CON register.
This bit is cleared by hardware when the corresponding interrupt vector is executed in case the
AC3IE in AC3CON 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 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
Table 24-7. Interrupt sensitivity selection
AC3IS[1:0] Description
00 Comparator Interrupt on output toggle
01 Reserved
10 Comparator interrupt on output falling edge
11 Comparator interrupt on output rising edge
Table 24-8. Analog Comparator 3 negative input selection
AC3M[2:0] Description
000 “Vref”/6.40
001 “Vref”/3.20
010 “Vref”/2.13
011 “Vref”/1.60
100 Bandgap (1.1V)
101 DAC result
110 Analog Comparator Negative Input (ACMPM pin)
111 Reserved
Bit 7 6 5 4 3 2 1 0
AC3IF AC2IF AC1IF AC0IF AC3O AC2O AC1O AC0O ACSR
Read/Write R/W R/W R/W R/W R R R R
Initial Value 0 0 0 0 0 0 0 0