DV164136 Microchip Technology, DV164136 Datasheet - Page 289

• Manufacturer Part Number: DV164136
• Description: DEVELOPMENT KIT FOR PIC18
• Manufacturer: Microchip Technology
• Series: PIC®r
• Type: MCUr

Specifications of DV164136

• Contents: Board, Cables, CDs, PICkit™ 3 Programmer, Power Supply
• Processor To Be Evaluated: PIC18F8722, PIC18F87J11
• Interface Type: RS-232, USB
• Operating Supply Voltage: 3.3 V, 5 V
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC18
• Silicon Core Number: PIC18F
• Silicon Family Name: PIC18F8xxx
• Kit Contents: PIC18 Exp Brd PICkit 3 Cable CD PSU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC18F8722, PIC18F87J11
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

23.0
The comparator voltage reference is a 16-tap resistor
ladder network that provides a selectable reference
voltage. Although its primary purpose is to provide a
reference for the analog comparators, it may also be
used independently of them.
A block diagram of the module is shown in Figure 23-1.
The resistor ladder is segmented to provide two ranges
of CV
conserve power when the reference is not being used.
The module’s supply reference can be provided from
either device V
23.1
The voltage reference module is controlled through the
CVRCON register (Register 23-1). 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
REGISTER 23-1:
© 2008 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6
bit 5
bit 4
bit 3-0
Note 1:
CVREN
R/W-0
REF
COMPARATOR VOLTAGE
REFERENCE MODULE
Configuring the Comparator
Voltage Reference
values and has a power-down function to
CVROE overrides the TRISF<5> bit setting.
DD
CVREN: Comparator Voltage Reference Enable bit
1 = CV
0 = CV
CVROE: Comparator V
1 = CV
0 = CV
CVRR: Comparator V
1 = 0 to 0.667 CV
0 = 0.25 CV
CVRSS: Comparator V
1 = Comparator reference source, CV
0 = Comparator reference source, CV
CVR<3:0>: Comparator V
When CVRR = 1:
CV
When CVRR = 0:
CV
/V
CVROE
SS
REF
REF
R/W-0
or an external voltage reference.
CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
= ((CVR<3:0>)/24) x (CV
= (CV
REF
REF
REF
REF
(1)
circuit powered on
circuit powered down
voltage level is also output on the RF5/AN10/CV
voltage is disconnected from the RF5/AN10/CV
RSRC
RSRC
W = Writable bit
‘1’ = Bit is set
R/W-0
CVRR
/4) + ((CVR<3:0>)/32) x (CV
RSRC
to 0.75 CV
REF
REF
REF
, with CV
Range Selection bit
REF
Source Selection bit
Output Enable bit
RSRC
Value Selection bits (0 ≤ (CVR<3:0>) ≤ 15)
CVRSS
RSRC
R/W-0
RSRC
, with CV
)
/24 step size (low range)
RSRC
RSRC
U = Unimplemented bit, read as ‘0’
RSRC
‘0’ = Bit is cleared
= (V
= AV
(1)
R/W-0
CVR3
RSRC
primary difference between the ranges is the size of the
steps
(CVR<3:0>), with one range offering finer resolution.
The equations used to calculate the output of the
comparator voltage reference are as follows:
The comparator reference supply voltage can come
from either V
V
voltage source is selected by the CVRSS bit
(CVRCON<4>).
The settling time of the comparator voltage reference
must be considered when changing the CV
Characteristics”).
output (see Table 28-3 in Section 28.0 “Electrical
PIC18F8722 FAMILY
/32 step size (high range)
REF
REF
DD
If CVRR = 1:
CV
If CVRR = 0:
CV
(CV
)
- that are multiplexed with RA2 and RA3. The
+) – (V
– AV
REF
REF
selected
RSRC
SS
= ((CVR3:CVR0)/24) x (CV
= (CV
REF
REF
REF
)
DD
R/W-0
CVR2
-)
pin
and V
pin
RSRC
by
/4) + ((CVR3:CVR0)/32) x
SS
the
, or the external V
x = Bit is unknown
R/W-0
CV
CVR1
REF
DS39646C-page 287
RSRC
Selection
)
R/W-0
CVR0
REF
+ and
bit 0
REF
bits