PIC18F45J10 FAMILY
19.0
COMPARATOR MODULE
The analog comparator module contains two
comparators that can be configured in a variety of
ways. The inputs can be selected from the analog
inputs multiplexed with pins RA0 through RA5, as well
as the on-chip voltage reference (see
The digi-
tal outputs (normal or inverted) are available at the pin
level and can also be read through the control register.
The CMCON register (Register 19.1) selects the
comparator input and output configuration. Block
diagrams of the various comparator configurations are
shown in Figure 19-1.
REGISTER 19-1:
R-0
C2OUT
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
CMCON: COMPARATOR CONTROL REGISTER
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
bit 0
C1OUT
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
C2OUT:
Comparator 2 Output bit
When C2INV =
0:
1
= C2 V
IN
+ > C2 V
IN
-
0
= C2 V
IN
+ < C2 V
IN
-
When C2INV =
1:
1
= C2 V
IN
+ < C2 V
IN
-
0
= C2 V
IN
+ > C2 V
IN
-
C1OUT:
Comparator 1 Output bit
When C1INV =
0:
1
= C1 V
IN
+ > C1 V
IN
-
0
= C1 V
IN
+ < C1 V
IN
-
When C1INV =
1:
1
= C1 V
IN
+ < C1 V
IN
-
0
= C1 V
IN
+ > C1 V
IN
-
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 CM<2:0> =
110:
1
= C1 V
IN
- connects to RA3/AN3/V
REF
+
C2 V
IN
- connects to RA2/AN2/V
REF
-/CV
REF
0
= C1 V
IN
- connects to RA0/AN0
C2 V
IN
- connects to RA1/AN1
CM<2:0>:
Comparator Mode bits
bit 6
bit 5
bit 4
bit 3
bit 2-0
©
2009 Microchip Technology Inc.
DS39682E-page 225
MICROCHIP [ MICROCHIP TECHNOLOGY ]
