PIC12F639 Microchip Technology, PIC12F639 Datasheet - Page 70

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PIC12F639

Manufacturer Part Number
PIC12F639
Description
(PIC12F635 / PIC12F636 / PIC12F639) 8/14-PIN FLASH-BASED / 8-BIT CMOS MICROCONTROLLERS WITH NANOWATT TECHNOLOGY
Manufacturer
Microchip Technology
Datasheet
PIC12F635/PIC16F636/639
7.6
The comparator module also allows the selection of an
internally generated voltage reference for one of the
comparator inputs. The VRCON register (Register 7-3)
controls the voltage reference module shown in
Figure 7-8.
7.6.1
The voltage reference can output 32 distinct voltage
levels, 16 in a high range and 16 in a low range.
The following equation determines the output voltages:
FIGURE 7-8:
DS41232B-page 68
V
DD
Comparator Reference
Comparator
CV
CONFIGURING THE VOLTAGE
REFERENCE
REF
VREN
Input
to
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
VR<3:0>
16-1 Analog
8R
MUX
R
Preliminary
R
16 Stages
EQUATION 7-1:
7.6.2
The voltage reference is V
CV
tested absolute accuracy of the comparator voltage
reference can be found in Section 15.0 “Electrical
Specifications”.
VRR = 1 (low range): CV
VRR = 0 (high range):
CV
REF
REF
output changes with fluctuations in V
R
= (V
VOLTAGE REFERENCE
ACCURACY/ERROR
DD
/4) + (VR<3:0> x V
R
© 2005 Microchip Technology Inc.
DD
REF
derived and therefore, the
= (VR<3:0>/24) x V
8R
DD
/32)
DD
VRR
. The
DD

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