PIC18F45J10 Datasheet, PDF (222/358 Pages) Microchip Technology – 28/40/44-Pin High-Performance RISC Microcontrollers with nanoWatt Technology

PIC18F45J10 FAMILY
18.1 Comparator Configuration
There are eight modes of operation for the compara-
tors, shown in Figure 18-1. Bits CM2:CM0 of the
CMCON register are used to select these modes. The
TRISA register controls the data direction of the com-
parator pins for each mode. If the Comparator mode is
changed, the comparator output level may not be valid
for the specified mode change delay shown in
Section 23.0 “Electrical Characteristics”.
Note:
Comparator interrupts should be disabled
during a Comparator mode change;
otherwise, a false interrupt may occur.
FIGURE 18-1:
COMPARATOR I/O OPERATING MODES
Comparators Reset
CM2:CM0 = 000
Comparators Off (POR Default Value)
CM2:CM0 = 111
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
VIN-
VIN+ ^C1
Off (Read as ‘0’)
RA0/AN0 ^D
RA3/AN3/ ^D
VREF+
VIN-
VIN+ ^C1
Off (Read as ‘0’)
RA1/AN1 ^A
RA2/AN2/ ^A
VREF-/CVREF
VIN-
VIN+ ^C2
Two Independent Comparators
CM2:CM0 = 010
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
VIN-
VIN+ ^C1
RA1/AN1 ^A
RA2/AN2/ ^A
VREF-/CVREF
VIN-
VIN+ ^C2
Off (Read as ‘0’)
C1OUT
C2OUT
Two Common Reference Comparators
CM2:CM0 = 100
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
VIN-
VIN+ ^C1
C1OUT
RA1/AN1 ^A
RA2/AN2/ ^D
VREF-/CVREF
VIN-
VIN+ ^C2
C2OUT
RA1/AN1 ^D
RA2/AN2/ D
VREF-/CVREF
VIN-
VIN+ ^C2
Off (Read as ‘0’)
Two Independent Comparators with Outputs
CM2:CM0 = 011
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
RB5/KBI1/
T0CKI/C1OUT*
RA1/AN1 ^A
RA2/AN2/ ^A
VREF-/CVREF
VIN-
VIN+ ^C1
VIN-
VIN+ ^C2
C1OUT
C2OUT
RA5/AN4/SS1/C2OUT*
Two Common Reference Comparators with Outputs
CM2:CM0 = 101
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
RB5/KBI1/
T0CKI/C1OUT*
VIN-
VIN+ ^C1
C1OUT
RA1/AN1 ^A
RA2/AN2/ ^D
VREF-/CVREF
VIN-
VIN+ ^C2
C2OUT
RA5/AN4/SS1/C2OUT*
One Independent Comparator with Output
CM2:CM0 = 001
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
VIN-
VIN+ ^C1
RB5/KBI1/T0CKI/C1OUT*
C1OUT
RA1/AN1 ^D
RA2/AN2/ ^D
VREF-/CVREF/
VIN-
VIN+ ^C2
Off (Read as ‘0’)
Four Inputs Multiplexed to Two Comparators
CM2:CM0 = 110
RA0/AN0 ^A
RA3/AN3/ ^A
VREF+
CIS = 0
CIS = 1
VIN-
VIN+ ^C1
RA1/AN1 ^A
RA2/AN2/ ^A
VREF-/CVREF/
CIS = 0
CIS = 1
VIN-
VIN+ ^C2
C1OUT
C2OUT
CVREF _{From VREF Module}
A = Analog Input, port reads zeros always
D = Digital Input
CIS (CMCON<3>) is the Comparator Input Switch
* Setting the TRISA<5> bit will disable the comparator outputs by configuring the pins as inputs.
DS39682C-page 220
Preliminary
© 2007 Microchip Technology Inc.