PIC18FXX20
20.0
COMPARATOR MODULE
The comparator module contains two analog compara-
tors. The inputs to the comparators are multiplexed
with the RF1 through RF6 pins. The on-chip Voltage
Reference (Section 21.0) can also be an input to the
comparators.
The CMCON register, shown as Register 20-1, con-
trols the comparator input and output multiplexers. A
block diagram of the various comparator configurations
is shown in Figure 20-1.
REGISTER 20-1:
CMCON REGISTER
R-0
C2OUT
bit 7
R-0
C1OUT
R/W-0
C2INV
R/W-0
C1INV
R/W-0
CIS
R/W-0
CM2
R/W-0
CM1
R/W-0
CM0
bit 0
bit 7
C2OUT:
Comparator 2 Output bit
When C2INV =
0:
1
= C2 V
IN
+ > C2 V
IN
-
0
= C2 V
IN
+ < C2 V
IN
-
When C2INV =
1:
1
= C2 V
IN
+ < C2 V
IN
-
0
= C2 V
IN
+ > C2 V
IN
-
C1OUT:
Comparator 1 Output bit
When C1INV =
0:
1
= C1 V
IN
+ > C1 V
IN
-
0
= C1 V
IN
+ < C1 V
IN
-
When C1INV =
1:
1
= C1 V
IN
+ < C1 V
IN
-
0
= C1 V
IN
+ > C1 V
IN
-
C2INV:
Comparator 2 Output Inversion bit
1
= C2 output inverted
0
= C2 output not inverted
C1INV:
Comparator 1 Output Inversion bit
1
= C1 Output inverted
0
= C1 Output not inverted
CIS:
Comparator Input Switch bit
When CM2:CM0 =
110:
1
= C1 V
IN
- connects to RF5/AN10
C2 V
IN
- connects to RF3/AN8
0
= C1 V
IN
- connects to RF6/AN11
C2 V
IN
- connects to RF4/AN9
CM2:CM0:
Comparator Mode bits
Legend:
R = Readable bit
- n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 6
bit 5
bit 4
bit 3
bit 2
2003 Microchip Technology Inc.
Advance Information
DS39609A-page 223
MICROCHIP [ MICROCHIP TECHNOLOGY ]
