PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 238

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18CXX8
19.1
There are eight modes of operation for the compara-
tors. The CMCON register is used to select these
modes. Figure 19-1 shows the eight possible modes.
The TRISF register controls the data direction of the
comparator pins for each mode. If the Comparator
FIGURE 19-1: COMPARATOR I/O OPERATING MODES
DS30475A-page 238
Comparators Reset (POR Default Value)
CM2:CM0 = 000
Two Independent Comparators
CM2:CM0 = 010
Two Common Reference Comparators
CM2:CM0 = 100
One Independent Comparator with Output
CM2:CM0 = 001
A = Analog Input, port reads zeros always.
D = Digital Input.
CIS (CMCON<3>) is the Comparator Input Switch.
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
RF2/AN7/C1OUT
Comparator Configuration
A
A
A
A
A
A
A
A
A
A
A
D
A
A
D
D
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
C1
C2
C1
C2
C1
C2
C1
C2
Off
Off
C1OUT
C2OUT
C1OUT
C2OUT
C1OUT
Off
(Read as ’0’)
(Read as ’0’)
(Read as ’0’)
Advanced Information
Two Independent Comparators with Outputs
CM2:CM0 = 011
Two Common Reference Comparators with Outputs
CM2:CM0 = 101
Comparators Off
CM2:CM0 = 111
Four Inputs Multiplexed to Two Comparators
CM2:CM0 = 110
RF2/AN7/C1OUT
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
RF1/AN6/C2OUT
RF6/AN11
RF5/AN10
RF2/AN7/C1OUT
RF4/AN9
RF3/AN8
RF1/AN6/C2OUT
mode is changed, the comparator output level may not
be valid for the specified mode change delay shown in
Electrical Specifications (Section 25.0).
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
RF6/AN11
RF5/AN10
RF4/AN9
RF3/AN8
Note:
A
A
A
D
A
A
A
A
D
D
D
D
A
A
A
A
Comparator interrupts should be disabled
during a Comparator mode change. Other-
wise, a false interrupt may occur.
V
V
V
V
V
V
V
V
V
V
V
V
CIS = 0
CIS = 1
CIS = 0
CIS = 1
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
-
+
-
+
-
+
-
+
-
+
-
+
C1
C2
C1
C2
C1
C2
2000 Microchip Technology Inc.
V
V
V
V
IN
IN
IN
IN
CV
-
+
-
+
REF
C1OUT
C2OUT
C1OUT
C2OUT
Off
Off
C1
C2
From V
(Read as ’0’)
(Read as ’0’)
REF
C1OUT
C2OUT
Module