PIC16F747 Microchip Technology Inc., PIC16F747 Datasheet - Page 164

• Manufacturer Part Number: PIC16F747
• Description: 28/40/44-pin, 8-bit Cmos Flash Microcontrollers With 10-bit A/d And Nanowatt Technology
• Manufacturer: Microchip Technology Inc.

PIC16F7X7
13.1
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
FIGURE 13-1:
DS30498C-page 162
Comparators Reset
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
RA2/AN2/
V
RA0/AN0
RA3/AN3/
V
RA1/AN1
RA2/AN2/
V
RA0/AN0
RA3/AN3/
V
RA1/AN1
RA0/AN0
RA3/AN3/
V
RA1/AN1
RA2/AN2/
V
RA0/AN0
RA3/AN3/
V
RA4/T0CKI/C1OUT
RA1/AN1
RA2/AN2/
V
REF
REF
REF
REF
REF
REF
REF
REF
-/CV
+
-/CV
+
+
-/CV
+
-/CV
Comparator Configuration
REF
REF
REF
REF
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
COMPARATOR I/O OPERATING MODES
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
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’)
D = Digital Input
CIS (CMCON<3>) is the Comparator Input Switch
Two Common Reference Comparators with Outputs
CM2:CM0 = 101
Two Independent Comparators with Outputs
CM2:CM0 = 011
RA4/T0CKI/C1OUT
RA3/AN3/
V
Comparators Off (POR Default Mode)
CM2:CM0 = 111
RA0/AN0
RA1/AN1
RA2/AN2/
V
RA5/AN4/LVDIN/SS/C2OUT
Four Inputs Multiplexed to Two Comparators
CM2:CM0 = 110
REF
REF
RA0/AN0
RA3/AN3/
V
RA4/T0CKI/C1OUT
RA1/AN1
RA2/AN2/
V
RA5/AN4/LVDIN/SS/C2OUT
RA3/AN3/
V
RA0/AN0
RA3/AN3/
V
RA1/AN1
RA2/AN2/
V
RA0/AN0
RA1/AN1
RA2/AN2/
V
be valid for the specified mode change delay shown in
the electrical specifications (Section 18.0 “Electrical
Characteristics”).
REF
REF
REF
REF
REF
REF
Note:
+
-/CV
+
-/CV
+
+
-/CV
-/CV
REF
REF
REF
REF
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.
Otherwise, 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
 2004 Microchip Technology Inc.
C1
C2
C1
C2
V
V
V
V
IN
IN
IN
IN
CV
-
+
-
+
REF
C1OUT
C2OUT
C1OUT
C2OUT
Off
Off
C1
C2
From Comparator
V
(Read as ‘0’)
(Read as
REF
Module
C1OUT
C2OUT
‘
0
’
)