PIC18F2585_07 Datasheet, PDF (259/482 Pages) Microchip Technology – Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology

PIC18F2585/2680/4585/4680
20.0 COMPARATOR MODULE
The analog comparator module contains two compara-
tors 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 volt-
age reference (see Section 21.0 “Comparator Voltage
Reference Module”). The digital outputs (normal or
inverted) are available at the pin level and can also be
read through the control register.
The CMCON register (Register 20-1) selects the
comparator input and output configuration. Block
diagrams of the various comparator configurations are
shown in Figure 20-1.
REGISTER 20-1:
CMCON: COMPARATOR CONTROL REGISTER
R-0
R-0
R/W-0 R/W-0 R/W-0
C2OUT C1OUT C2INV C1INV
CIS
bit 7
R/W-0
CM2
R/W-0
CM1
R/W-0
CM0
bit 0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
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-
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-
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 RD0/PSP0/C1IN+
C2 VIN- connects to RD2/PSP2/C2IN+
0 = C1 VIN- connects to RD1/PSP1/C1IN-
C2 VIN- connects to RD3/PSP3/C2IN-
CM2:CM0: Comparator Mode bits
Figure 20-1 shows the Comparator modes and the CM2:CM0 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
© 2007 Microchip Technology Inc.
Preliminary
DS39625C-page 257