DV164136 Microchip Technology, DV164136 Datasheet - Page 313

• 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

23.2
The full range of voltage reference cannot be realized
due to the construction of the module. The transistors
on the top and bottom of the resistor ladder network
(Figure 23-1) keep CV
ence source rails. The voltage reference is derived
from the reference source; therefore, the CV
changes with fluctuations in that source. The tested
absolute accuracy of the voltage reference can be
found in Section 27.0 “Electrical Characteristics”.
23.3
The voltage reference module operates independently
of the comparator module. The output of the reference
generator may be connected to the RF5 pin if the
CVROE bit is set. Enabling the voltage reference out-
put onto RA2 when it is configured as a digital input will
increase current consumption. Connecting RF5 as a
digital output with CVRSS enabled will also increase
current consumption.
FIGURE 23-2:
TABLE 23-1:
© 2009 Microchip Technology Inc.
CVRCON
CM1CON
CM2CON
TRISA
TRISF
ANCON0
ANCON1
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used with the comparator voltage reference.
Note 1:
Name
Note 1:
2:
Voltage Reference Accuracy/Error
Connection Considerations
(2)
(2)
(2)
These bits are only available in select oscillator modes (FOSC2 Configuration bit = 0); otherwise, they are
unimplemented.
Configuration SFR, overlaps with default SFR at this address; available only when WDTCON<4> = 1.
TRISA7
PCFG15
R is dependent upon the comparator voltage reference configuration bits, CVRCON<5> and CVRCON<3:0>.
CVREN
TRISF7
PCFG7
CON
CON
Bit 7
REGISTERS ASSOCIATED WITH COMPARATOR VOLTAGE REFERENCE
CV
Module
REF
COMPARATOR VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
REF
PIC18F87J11
(1)
from approaching the refer-
TRISA6
PCFG14
CVROE
TRISF6
PCFG6
COE
COE
Bit 6
Impedance
Reference
Voltage
Output
R
(1)
(1)
PCFG13 PCFG12
TRISA5
TRISF5
CVRR
CPOL
CPOL
Bit 5
—
REF
RF5
output
EVPOL1
EVPOL1
CVRSS
TRISA4
TRISF4
PCFG4
Bit 4
EVPOL0
EVPOL0
PCFG11
TRISA3
TRISF3
PCFG3
PIC18F87J11 FAMILY
CVR3
Bit 3
The RF5 pin can be used as a simple D/A output with
limited drive capability. Due to the limited current drive
capability, a buffer must be used on the voltage
reference output for external connections to V
Figure 23-2 shows an example buffering technique.
23.4
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the CVRCON register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
23.5
A device Reset disables the voltage reference by
clearing CVREN (CVRCON<7>). This Reset also
disconnects the reference from the RA2 pin by clearing
CVROE, and selects the high-voltage range by clearing
CVRR. The CVR value select bits are also cleared.
+
–
Operation During Sleep
Effects of a Reset
PCFG10
TRISA2
TRISF2
PCFG2
CVR2
CREF
CREF
Bit 2
TRISA1
TRISF1
PCFG1
PCFG9
CCH1
CCH1
CVR1
CV
Bit 1
REF
Output
TRISA0
PCFG0
PCFG8
CVR0
CCH0
CCH0
Bit 0
DS39778D-page 313
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on Page:
Values
Reset
61
58
58
60
60
59
59
REF
.