Datasheet

PIC18F2220/2320/4220/4320
DS39599G-page 222 © 2007 Microchip Technology Inc.
FIGURE 20-1: COMPARATOR I/O OPERATING MODES
Comparators RESET
CM<2:0> = 000
C1
RA0/AN0
V
IN-
V
IN+
RA3/AN3/
C1OUT
Two Independent Comparators
A
A
CM<2:0> = 010
C2
RA1/AN1
V
IN-
V
IN+
RA2/AN2/
C2OUT
A
A
C1
V
IN-
V
IN+
C1OUT
Two Common Reference Comparators
A
A
CM<2:0> = 100
C2
V
IN-
V
IN+
C2OUT
A
D
C2
V
IN-
V
IN+
Off (Read as ‘0’)
One Independent Comparator with Output
D
D
CM<2:0> = 001
C1
V
IN-
V
IN+
C1OUT
A
A
C1
V
IN-
V
IN+
Off (Read as ‘0’)
Comparators Off (POR Default Value)
D
D
CM<2:0> = 111
C2
V
IN-
V
IN+
Off (Read as ‘0’)
D
D
C1
V
IN-
V
IN+
C1OUT
Four Inputs Multiplexed to Two Comparators
A
A
CM<2:0> = 110
C2
V
IN-
V
IN+
C2OUT
A
A
From VREF Module
CIS = 0
CIS = 1
CIS = 0
CIS = 1
C1
V
IN-
V
IN+
C1OUT
Two Common Reference Comparators with Outputs
A
A
CM<2:0> = 101
C2
V
IN-
V
IN+
C2OUT
A
D
A = Analog Input, port reads zeros always, overrides TRISA bit
(2)
.
D = Digital Input.
CIS (CMCON<3>) is the Comparator Input Switch; CVROE (CVRCON<6>) is the Voltage Reference Output Switch.
CV
REF
C1
V
IN-
V
IN+
C1OUT
Two Independent Comparators with Outputs
A
A
CM<2:0> = 011
C2
V
IN-
V
IN+
C2OUT
A
A
RA4/T0CKI/C1OUT
(1)
RA5/AN4/SS/LVDIN/C2OUT
(1)
RA4/T0CKI/C1OUT
(1)
RA5/AN4/SS/LVDIN/C2OUT
(1)
RA4/T0CKI/C1OUT
(1)
RA3/AN3/
RA1/AN1
RA2/AN2/
RA0/AN0
RA0/AN0
RA3/AN3/
RA1/AN1
RA2/AN2/
RA0/AN0
RA3/AN3/
RA1/AN1
RA2/AN2/
RA0/AN0
RA3/AN3/
RA1/AN1
RA2/AN2/
RA0/AN0
RA3/AN3/
RA1/AN1
RA2/AN2/
RA0/AN0
RA3/AN3/
RA1/AN1
RA2/AN2/
V
REF+
V
REF-/CVREF
VREF+
V
REF-/CVREF
VREF+
Note 1: RA4 must be configured as an output pin in TRISA<4> when used to output C1OUT. RA5 ignores TRISA<5> when
used as an output for C2OUT.
2: Mode 110 is exception. Comparator input pins obey TRISA bits.
VREF-/CVREF
VREF-/CVREF
CVROE = 1
CVROE = 0
VREF+
V
REF-/CVREF
VREF+
V
REF+
V
REF-/CVREF
VREF+
V
REF-/CVREF
C1
V
IN-
V
IN+
Off (Read as ‘0’)
D
D
C2
V
IN-
V
IN+
Off (Read as ‘0’)
D
D
RA3/AN3/
RA1/AN1
RA2/AN2/
RA0/AN0
V
REF+
V
REF-/CVREF