PIC24FJ128GA010_09 Datasheet, PDF (187/240 Pages) Microchip Technology – 64/80/100-Pin General Purpose, 16-Bit Flash Microcontrollers

PIC24FJ128GA010 FAMILY
22.0 COMPARATOR VOLTAGE
REFERENCE
Note:
This data sheet summarizes features of
PIC24F group of devices and is not
intended to be a comprehensive reference
source. Refer to Section 20. “Compara-
tor Voltage Reference Module”
(DS39709) in the “PIC24F Family
Reference Manual” for more information.
22.1 Configuring the Comparator
Voltage Reference
The voltage reference module is controlled through the
CVRCON register (Register 22-1). The comparator
voltage reference provides two ranges of output
voltage, each with 16 distinct levels. The range to be
used is selected by the CVRR bit (CVRCON<5>). The
primary difference between the ranges is the size of the
steps selected by the CVREF Selection bits
(CVR3:CVR0), with one range offering finer resolution.
The comparator reference supply voltage can come
from either VDD and VSS, or the external VREF+ and
VREF-. The voltage source is selected by the CVRSS
bit (CVRCON<4>).
The settling time of the comparator voltage reference
must be considered when changing the CVREF
output.
CVRR: Comparator VREF Range Selection bit 1 = 0
to 0.625 CVRSRC, with CVRSRC/24 step size
0 = 0.25 CVRSRC to 0.72 CVRSRC, with CVRSRC/
32 step size
FIGURE 22-1:
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
VREF+ ^{CVRSS = 1}
AVDD
CVRSS = 0
8R
CVREN
R
R
R
R
16 Steps
CVR3:CVR0
CVREF
R
R
R
CVRR
VREF-
8R
CVRSS = 1
CVRSS = 0
AVSS
© 2009 Microchip Technology Inc.
DS39747E-page 187