PCM18XK1 Microchip Technology, PCM18XK1 Datasheet - Page 268

• Manufacturer Part Number: PCM18XK1
• Description: MODULE PROC PIC18F8680,6680,8565
• Manufacturer: Microchip Technology

Specifications of PCM18XK1

• Accessory Type: Processor Module
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICE2000
• For Use With: ICE2000 - EMULATOR MPLAB-ICE 2000 POD
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC18F6585/8585/6680/8680
FIGURE 21-1:
21.2
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 21-1) 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”.
21.3
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.
DS30491C-page 266
CVREN
Note: R is defined in Section 27.0 “Electrical Characteristics”.
Voltage Reference Accuracy/Error
Operation During Sleep
CVRSS = 0
CV
REF
V
DD
REF
VOLTAGE REFERENCE BLOCK DIAGRAM
V
from approaching the refer-
REF
CVRSS = 1
+
8R
R
REF
output
R
16 Stages
16-1 Analog Mux
21.4
A device Reset disables the voltage reference by
clearing bit CVREN (CVRCON<7>). This Reset also
disconnects the reference from the RA2 pin by clearing
bit CVROE (CVRCON<6>) and selects the high-
voltage range by clearing bit CVRR (CVRCON<5>).
The VRSS value select bits, CVRCON<3:0>, are also
cleared.
21.5
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
TRISF<5> bit is set and the CVROE bit is set. Enabling
the voltage reference output onto the RF5 pin with an
input signal present will increase current consumption.
Connecting RF5 as a digital output with VRSS enabled
will also increase current consumption.
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 refer-
ence output for external connections to V
Figure 21-2 shows an example buffering technique.
R
Effects of a Reset
Connection Considerations
R
 2004 Microchip Technology Inc.
8R
CVR3
CVR0
(From CVRCON<3:0>)
CVRR
CVRSS = 0
CVRSS = 1
V
REF
-
REF
.