PIC16F737-I Datasheet, PDF (164/276 Pages) Microchip Technology – 28/40/44-Pin, 8-Bit CMOS Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC16F7X7
13.1 Comparator Configuration
There are eight modes of operation for the compara-
tors. The CMCON register is used to select these
modes. Figure 13-1 shows the eight possible modes.
The TRISA register controls the data direction of the
comparator 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
the electrical specifications (Section 18.0 “Electrical
Characteristics”).
Note:
Comparator interrupts should be disabled
during a Comparator mode change.
Otherwise, a false interrupt may occur.
FIGURE 13-1:
COMPARATOR I/O OPERATING MODES
Comparators Reset
CM2:CM0 = 000
Comparators Off (POR Default Mode)
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
VIN-
RA3/AN3/ A
VREF+
VIN+ ^C1
RA1/AN1 ^A
RA2/AN2/ ^A
VREF-/CVREF
VIN-
VIN+ ^C2
Off (Read as ‘0’)
C1OUT
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+
VIN-
VIN+ ^C1
C1OUT
RA4/T0CKI/C1OUT
RA1/AN1 ^A
RA2/AN2/ A
VREF-/CVREF
VIN-
VIN+ ^C2
RA5/AN4/LVDIN/SS/C2OUT
C2OUT
Two Common Reference Comparators
CM2:CM0 = 100
RA0/AN0 ^A
VIN-
RA3/AN3/ A
VREF+
VIN+ ^C1
C1OUT
RA1/AN1 ^A
RA2/AN2/ ^D
VREF-/CVREF
VIN-
VIN+ ^C2
C2OUT
Two Common Reference Comparators with Outputs
CM2:CM0 = 101
RA0/AN0 ^A
RA3/AN3/ A
VREF+
VIN-
VIN+ ^C1
C1OUT
RA4/T0CKI/C1OUT
RA1/AN1 ^A
RA2/AN2/ ^D
VREF-/CVREF
VIN-
VIN+ ^C2
RA5/AN4/LVDIN/SS/C2OUT
C2OUT
One Independent Comparator with Output
CM2:CM0 = 001
RA0/AN0 ^A
VIN-
RA3/AN3/ A
VREF+
VIN+ ^C1
RA4/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 VIN-
CIS = 1
VIN+
C2
C1OUT
C2OUT
CVREF _{From Comparator}
VREF Module
A = Analog Input, port reads zeros always D = Digital Input CIS (CMCON<3>) is the Comparator Input Switch
DS30498C-page 162
 2004 Microchip Technology Inc.