PIC16F87XA
The CMCON register (Register 12-1) controls the com-
parator input and output multiplexers. A block diagram
of the various comparator configurations is shown in
Figure 12-1.
12.0 COMPARATOR MODULE
The comparator module contains two analog compara-
tors. The inputs to the comparators are multiplexed
with I/O port pins RA0 through RA3, while the outputs
are multiplexed to pins RA4 and RA5. The on-chip Volt-
age Reference (Section 13.0) can also be an input to
the comparators.
REGISTER 12-1: CMCON REGISTER
R-0
R-0
R/W-0
C2INV
R/W-0
C1INV
R/W-0
CIS
R/W-1
CM2
R/W-1
CM1
R/W-1
CM0
C2OUT
C1OUT
bit 7
bit 0
bit 7
C2OUT: Comparator 2 Output bit
When C2INV = 0:
1= C2 VIN+ > C2 VIN–
0= C2 VIN+ < C2 VIN–
When C2INV = 1:
1= C2 VIN+ < C2 VIN–
0= C2 VIN+ > C2 VIN–
bit 6
C1OUT: Comparator 1 Output bit
When C1INV = 0:
1= C1 VIN+ > C1 VIN–
0= C1 VIN+ < C1 VIN–
When C1INV = 1:
1= C1 VIN+ < C1 VIN–
0= C1 VIN+ > C1 VIN–
bit 5
bit 4
bit 3
C2INV: Comparator 2 Output Inversion bit
1= C2 output inverted
0= C2 output not inverted
C1INV: Comparator 1 Output Inversion bit
1= C1 Output inverted
0= C1 Output not inverted
CIS: Comparator Input Switch bit
When CM2:CM0 = 110:
1= C1 VIN– connects to RA3/AN3
C2 VIN– connects to RA2/AN2
0= C1 VIN– connects to RA0/AN0
C2 VIN– connects to RA1/AN1
bit 2
CM2:CM0: Comparator Mode bits
Figure 12-1 shows the Comparator modes and CM2:CM0 bit settings
Legend:
R = Readable bit
W = Writable bit
’1’ = Bit is set
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
2001 Microchip Technology Inc.
Advance Information
DS39582A-page 133
MICROCHIP [ MICROCHIP ]
