PIC12F635/PIC16F636/639
7.7
Operation During Sleep
7.8
Effects of a Reset
The comparator, if enabled before entering Sleep mode,
remains active during Sleep. The additional current
consumed by the comparator is shown separately in the
Section 15.0 “Electrical Specifications”. If the
comparator is not used to wake the device, power
consumption can be minimized while in Sleep mode by
turning off the comparator. The comparator is turned off
by selecting mode CM<2:0> = 000or CM<2:0> = 111
of the CMCON0 register.
A device Reset forces the CMCON0 and CMCON1
registers to their Reset states. This forces the Compar-
ator module to be in the Comparator Reset mode
(CM<2:0> = 000). Thus, all comparator inputs are
analog inputs with the comparator disabled to consume
the smallest current possible.
A change to the comparator output can wake-up the
device from Sleep. To enable the comparator to wake
the device from Sleep, the CxIE bit of the PIE1 register
and the PEIE bit of the INTCON register must be set.
The instruction following the Sleep instruction always
executes following a wake from Sleep. If the GIE bit of
the INTCON register is also set, the device will then
execute the Interrupt Service Routine.
REGISTER 7-1:
CMCON0: COMPARATOR CONFIGURATION REGISTER (PIC12F635)
U-0
—
R-0
U-0
—
R/W-0
CINV
R/W-0
CIS
R/W-0
CM2
R/W-0
CM1
R/W-0
CM0
COUT
bit 7
bit 0
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 7
bit 6
Unimplemented: Read as ‘0’
COUT: Comparator Output bit
When CINV = 0:
1= VIN+ > VIN-
0= VIN+ < VIN-
When CINV = 1:
1= VIN+ < VIN-
0= VIN+ > VIN-
bit 5
bit 4
Unimplemented: Read as ‘0’
CINV: Comparator Output Inversion bit
1= Output inverted
0= Output not inverted
bit 3
CIS: Comparator Input Switch bit
When CM<2:0> = 110or 101:
1= CIN+ connects to VIN-
0= CIN- connects to VIN-
When CM<2:0> = 0xxor 100or 111:
CIS has no effect.
bit 2-0
CM<2:0>: Comparator Mode bits (See Figure 7-5)
000= CIN pins are configured as analog, COUT pin configured as I/O, Comparator output turned off
001= CIN pins are configured as analog, COUT pin configured as Comparator output
010= CIN pins are configured as analog, COUT pin configured as I/O, Comparator output available internally
011= CIN- pin is configured as analog, CIN+ pin is configured as I/O, COUT pin configured as
Comparator output, CVREF is non-inverting input
100= CIN- pin is configured as analog, CIN+ pin is configured as I/O, COUT pin is configured as I/O, Comparator output
available internally, CVREF is non-inverting input
101= CIN pins are configured as analog and multiplexed, COUT pin is configured as
Comparator output, CVREF is non-inverting input
110= CIN pins are configured as analog and multiplexed, COUT pin is configured as I/O,
Comparator output available internally, CVREF is non-inverting input
111= CIN pins are configured as I/O, COUT pin is configured as I/O, Comparator output disabled, Comparator off.
© 2007 Microchip Technology Inc.
DS41232D-page 79
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