PIC16F688
7.0
COMPARATOR MODULE
The comparator module contains two analog
comparators. The inputs to the comparators are
multiplexed with I/O port pins RA0, RA1, RC0 and RC1,
while the outputs are multiplexed to pins RA2 and RC4.
An on-chip Comparator Voltage Reference (CV
REF
)
can also be applied to the inputs of the comparators.
The CMCON0 register (Register 7-1) controls the
comparator input and output multiplexers. A block
diagram of the various comparator configurations is
shown in Figure 7-3.
REGISTER 7-1:
CMCON0 – COMPARATOR CONFIGURATION REGISTER (ADDRESS: 19h)
R-0
C2OUT
bit 7
R-0
C1OUT
R/W-0
C2INV
R/W-0
C1INV
R/W-0
CIS
R/W-0
CM2
R/W-0
CM1
R/W-0
CM0
bit 0
bit 7
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> =
010:
1
= C1 V
IN
- connects to RA0/AN0
C2 V
IN
- connects to RC0/AN4
0
= C1 V
IN
- connects to RA1/AN1
C2 V
IN
- connects to RC1/AN5
When CM<2:0> =
001:
1
= C1 V
IN
- connects to RA0/AN0
0
= C1 V
IN
- connects to RA1/AN1
CM<2:0>:
Comparator Mode bits
Legend:
R = Readable bit
- n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 6
bit 5
bit 4
bit 3
bit 2
2004 Microchip Technology Inc.
Preliminary
DS41203B-page 53
MICROCHIP [ MICROCHIP TECHNOLOGY ]
