Datasheet

 2003-2013 Microchip Technology Inc. DS39612C-page 243
PIC18F6525/6621/8525/8621
21.0 COMPARATOR MODULE
The comparator module contains two analog
comparators. The inputs to the comparators are
multiplexed with the RF1 through RF6 pins. The on-
chip Voltage Reference (Section 22.0 “Comparator
Voltage Reference Module”) can also be an input to
the comparators.
The CMCON register, shown as Register 21-1, con-
trols the comparator input and output multiplexers. A
block diagram of the various comparator configurations
is shown in Figure 21-1.
REGISTER 21-1: CMCON: COMPARATOR CONTROL REGISTER
R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
C2OUT C1OUT C2INV C1INV CIS CM2 CM1 CM0
bit 7 bit 0
bit 7 C2OUT: Comparator 2 Output bit
When C2INV =
0:
1 = C2 VIN+ > C2 VIN-
0 = C2 V
IN+ < C2 VIN-
When C2INV = 1:
1 = C2 VIN+ < C2 VIN-
0 = C2 V
IN+ > C2 VIN-
bit 6 C1OUT: Comparator 1 Output bit
When C1INV = 0:
1 = C1 VIN+ > C1 VIN-
0 = C1 V
IN+ < C1 VIN-
When C1INV = 1:
1 = C1 VIN+ < C1 VIN-
0 = C1 V
IN+ > C1 VIN-
bit 5 C2INV: Comparator 2 Output Inversion bit
1 = C2 output inverted
0 = C2 output not inverted
bit 4 C1INV: Comparator 1 Output Inversion bit
1 = C1 output inverted
0 = C1 output not inverted
bit 3 CIS: Comparator Input Switch bit
When CM2:CM0 = 110:
1 =C1 VIN- 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
bit 2-0 CM2:CM0: Comparator Mode bits
Figure 21-1 shows the Comparator modes and the CM2:CM0 bit settings.
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown