AC162078 Microchip Technology, AC162078 Datasheet - Page 183

• Manufacturer Part Number: AC162078
• Description: HEADER INTRFC MPLAB ICD2 18F1330
• Manufacturer: Microchip Technology

Specifications of AC162078

• Accessory Type: Transition Header
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICD2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

18.0
The comparator voltage reference is a 16-tap resistor
ladder network that provides a selectable reference
voltage. Its purpose is to provide a reference for the
analog comparators.
A block diagram of the module is shown in Figure 18-1.
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
18.1
The voltage reference module is controlled through the
CVRCON register (Register 18-1). 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
(CVR3:CVR0), with one range offering finer resolution.
The equations used to calculate the output of the
comparator voltage reference are as follows:
 2009 Microchip Technology Inc.
If CVRR = 1:
CV
If CVRR = 0:
CV
CV
REF
REF
REF
RSRC
selected
COMPARATOR VOLTAGE
REFERENCE MODULE
Configuring the Comparator
Voltage Reference
values and has a power-down function to
= (CV
= ((CVR3:CVR0)/24) x CV
)
DD
/V
RSRC
by
SS
or an external voltage reference.
x 1/4) + (((CVR3:CVR0)/32) x
the
CV
REF
RSRC
selection
bits
The comparator reference supply voltage can come
from either AV
multiplexed with RA4 and AV
selected by the CVRSS bit (CVRCON<4>).
Additionally, the voltage reference can select the
unscaled V
bypassing the CV
Figure 18-1.)
The settling time of the comparator voltage reference
must be considered when changing the CV
Characteristics”).
TABLE 18-1:
output (see Table 23-3 in Section 23.0 “Electrical
CVREN CVRSS
0
0
1
1
PIC18F1230/1330
REF
0
1
0
1
DD
+ input for use by the comparators,
or AV
VOLTAGE REFERENCE
OUTPUT
REF
Disabled
Disabled
Enabled
Enabled
C
VREF
SS
module. (See Table 18-1 and
, or the external V
SS
No reference
From V
(CV
From CV
From CV
. The voltage source is
REF
Comparator Input
DS39758D-page 183
REF
bypassed)
REF
REF
REF
+ that is
REF