Vault 7: Projects
This publication series is about specific projects related to the Vault 7 main publication.
© 2010 Microchip Technology Inc. Preliminary DS39741A-page 48-21
Section 48. Comparator with Blanking
Comparator with
Blanking
48
48.6 COMPARATOR VOLTAGE REFERENCE GENERATOR
The internal comparator voltage reference is derived from a 16-tap resistor ladder network that
provides a selectable voltage level, as illustrated in Figure 48-7. This resistor network generates
the internal voltage reference for the analog comparators.
This voltage generator network is managed by the Comparator Voltage Reference
Control (CVRCON) register (see Register 48-6) through these control bits:
• CVREN – Comparator Voltage Reference Enable bit (CVRCON<7>)
This control bit enables the voltage reference circuit.
• CVROE – Comparator Voltage Reference Output Enable bit (CVRCON<6>)
This control bit enables the reference voltage to be placed on the CV
REF pin. When enabled,
this bit overrides the corresponding TRIS bit setting.
• VREFSEL – Voltage Reference Select bit (CVRCON<10>)
This control bit specifies whether the reference source is external (V
REF+), or it is obtained
from the 4-bit DAC output.
• CVRSS – Comparator Voltage Reference Source Selection bit (CVRCON<4>)
This control bit specifies that the source (CVRSS) for the voltage reference circuit is either
the device voltage supply (AV
DD and AVSS) or an external reference (VREF+ and VREF-).
• CVRR – Comparator Voltage Reference Range Selection bit (CVRCON<5>)
This control bit selects one of the two voltage ranges covered by the 16-tap resistor ladder
network:
- 0 CV
RSRC to 0.67 CVRSRC
- 0.25 CVRSRC to 0.75 CVRSRC
The range selected also determines the voltage increments available from the resistor
ladder taps (see 48.6.1 “Configuring the Comparator Voltage Reference”).
• CVR<3:0> – Comparator Voltage Reference Value Selection bits (CVRCOM<3:0>)
These bits designate the resistor ladder tap position.
Table 48-1 lists the voltage at each tap for both ranges with CV
RSRC = 3.3V.
Figure 48-7: Comparator Voltage Reference Block Diagram
16-to-1 MUX
8R
R
CVREN
AV
DD
(1)
8R
R
R
R
R
R
R
16 Steps
CVRR
CVREF
CVR3
CVR2
CVR1
CVR0
CVRCON<3:0>
AVSS
(1)
CVRSRC
CVRCON<CVROE>
CVREFIN
VREFSEL
Note 1: This pin is VDD and VSS on devices that have
no AV
DD or AVSS pins.
Protego_Release_01_05-Related-OEM-Documentation-PIC24FJ32MC10X-Reference_Manual-Section48-Comparator_with_Blanking.pdf