PIC16C620 Microchip Technology, PIC16C620 Datasheet - Page 38

• Manufacturer Part Number: PIC16C620
• Description: EPROM-Based 8-Bit CMOS Microcontroller
• Manufacturer: Microchip Technology

PIC16C62X
7.1
There are eight modes of operation for the
comparators. The CMCON register is used to select the
mode. Figure 7-2 shows the eight possible modes. The
TRISA register controls the data direction of the com-
parator pins for each mode. If the comparator mode is
FIGURE 7-2:
DS30235G-page 38
A = Analog Input, Port Reads Zeros Always
D = Digital Input
CIS = CMCON<3>, Comparator Input Switch
RA3/AN3
RA1/AN1
RA2/AN2
RA3/AN3
RA1/AN1
RA2/AN2
RA3/AN3
RA2/AN2
RA0/AN0
RA0/AN0
RA0/AN0
RA1/AN1
RA3/AN3
RA2/AN2
Comparators Reset
Two Independent Comparators
Two Common Reference Comparators
One Independent Comparator
RA0/AN0
RA1/AN1
Comparator Configuration
A
A
A
A
D
D
A
A
A
A
A
D
A
A
A
A
COMPARATOR I/O OPERATING MODES
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
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
C2
C2
C1
C1
C1
C2
C1
C2
CM<2:0> = 000
CM<2:0> = 100
CM<2:0> = 011
CM<2:0> = 101
C1OUT
C2OUT
C1OUT
C2OUT
(Read as '0')
(Read as '0')
(Read as '0')
C2OUT
Off
Off
Off
Preliminary
RA3/AN3
RA2/AN2
Comparators Off
Four Inputs Multiplexed to
Two Comparators
Two Common Reference Comparators with Outputs
Three Inputs Multiplexed to
Two Comparators
RA0/AN0
RA1/AN1
RA3/AN3
RA1/AN1
RA2/AN2
RA3/AN3
RA1/AN1
RA2/AN2
RA0/AN0
RA0/AN0
RA3/AN3
RA1/AN1
RA2/AN2
RA0/AN0
changed, the comparator output level may not be valid
for the specified mode change delay shown in
Table 12-2.
Note:
RA4 Open Drain
D
D
D
D
A
A
A
A
A
A
A
A
A
A
A
D
Comparator interrupts should be disabled
during a comparator mode change other-
wise a false interrupt may occur.
V
V
V
V
CIS=0
CIS=1
CIS=0
CIS=1
CIS=0
CIS=1
IN
IN
IN
IN
V
V
V
V
V
V
V
V
-
+
-
+
IN
IN
IN
IN
IN
IN
IN
IN
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
V
V
V
V
C1
C2
IN
IN
IN
IN
1998 Microchip Technology Inc.
C2
C1
C2
C1
-
+
-
+
-
+
-
+
From V
C2
CM<2:0> = 001
C1
CM<2:0> = 010
CM<2:0> = 111
CM<2:0> = 110
(Read as '0')
(Read as '0')
REF
C1OUT
C2OUT
C1OUT
C2OUT
Module
Off
Off
C2OUT
C1OUT