Datasheet

 2003-2013 Microchip Technology Inc. DS39609C-page 223
PIC18F6520/8520/6620/8620/6720/8720
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 ref-
erence (Section 21.0 “Comparator Voltage Reference
Module”) 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 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 20-1 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