PIC16F946 Datasheet, PDF (97/274 Pages) Microchip Technology – 64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt Technology

PIC16F946
8.0 COMPARATOR MODULE
The Comparator module contains two analog
comparators. The inputs to the comparators are
multiplexed with I/O port pins RA<3:0>, while the outputs
are multiplexed to pins RA<5:4>. An on-chip Comparator
Voltage Reference (CVREF) can also be applied to the
inputs of the comparators.
The CMCON0 register (Register 8-1) controls the
comparator input and output multiplexers. A block
diagram of the various comparator configurations is
shown in Figure 8-3.
REGISTER 8-1:
CMCON0 – COMPARATOR CONFIGURATION REGISTER (ADDRESS: 9Ch)
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
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:
0 = C2 VIN+ > C2 VIN-
1 = 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:
0 = C1 VIN+ > C1 VIN-
1 = 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 CM<2:0> = 010:
1 = C1 VIN- connects to RA3/AN3/C1+/VREF+/SEG15
C2 VIN- connects to RA2/AN2/C2+/VREF-/COM2
0 = C1 VIN- connects to RA0/AN0/C1-/SEG12
C2 VIN- connects to RA1/AN1/C2-/SEG7
When CM<2:0> = 001:
1 = C1 VIN- connects to RA3/AN3/C1+/VREF+/SEG15
0 = C1 VIN- connects to RA0/AN0/C1-/SEG12
When CM<2:0> = 101:
1 = C2 VIN+ connects to internal 0.6V reference
0 = C2 VIN+ connects to RA2/AN2/C2+/VREF-/COM2
CM<2:0>: Comparator Mode bits⁽¹⁾
See Figure 8-3 for comparator modes and CM<2:0> bit settings.
Note 1: Setting a pin to an analog input automatically disables the digital input circuitry,
weak pull-ups, and interrupt-on-change, if available. The corresponding TRIS bit
must be set to Input mode in order to allow external control of the voltage on the pin.
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
© 2005 Microchip Technology Inc.
Preliminary
DS41265A-page 95