PIC16F688 Datasheet, PDF (55/174 Pages) Microchip Technology – 14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

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 (CVREF)
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
R-0
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
C2OUT C1OUT C2INV C1INV
CIS
CM2
CM1
CM0
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
C2INV: Comparator 2 Output Inversion bit
1 = C2 output inverted
0 = C2 output not inverted
bit 4
C1INV: Comparator 1 Output Inversion bit
1 = C1 Output inverted
0 = C1 Output not inverted
bit 3
CIS: Comparator Input Switch bit
When CM<2:0> = 010:
1 = C1 VIN- connects to RA0/AN0
C2 VIN- connects to RC0/AN4
0 = C1 VIN- connects to RA1/AN1
C2 VIN- connects to RC1/AN5
When CM<2:0> = 001:
1 = C1 VIN- connects to RA0/AN0
0 = C1 VIN- connects to RA1/AN1
bit 2
CM<2:0>: Comparator Mode bits
Figure 7-3 shows the Comparator modes and CM<2:0> bit settings
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
 2004 Microchip Technology Inc.
Preliminary
DS41203B-page 53