Datasheet

© 2009 Microchip Technology Inc. DS41288F-page 71
PIC16F610/616/16HV610/616
8.11.5 FIXED VOLTAGE REFERENCE
The fixed voltage reference is independent of VDD, with
a nominal output voltage of 0.6V. This reference can be
enabled by setting the FVREN bit of the VRCON
register to ‘1’. This reference is always enabled when
the HFINTOSC oscillator is active.
8.11.6 FIXED VOLTAGE REFERENCE
STABILIZATION PERIOD
When the fixed voltage reference module is enabled, it
will require some time for the reference and its amplifier
circuits to stabilize. The user program must include a
small delay routine to allow the module to settle. See
the electrical specifications section for the minimum
delay requirement.
8.11.7 VOLTAGE REFERENCE
SELECTION
Multiplexers on the output of the voltage reference
module enable selection of either the CV
REF or fixed
voltage reference for use by the comparators.
Setting the C1VREN bit of the VRCON register enables
current to flow in the CV
REF voltage divider and selects
the CV
REF voltage for use by C1. Clearing the
C1VREN bit selects the fixed voltage for use by C1.
Setting the C2VREN bit of the VRCON register enables
current to flow in the CV
REF voltage divider and selects
the CV
REF voltage for use by C2. Clearing the
C2VREN bit selects the fixed voltage for use by C2.
When both the C1VREN and C2VREN bits are cleared,
current flow in the CV
REF voltage divider is disabled
minimizing the power drain of the voltage reference
peripheral.
FIGURE 8-9: COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
VRR
8R
VR<3:0>
(1)
Analog
8RRR RR
16 Stages
VDD
MUX
Fixed Voltage
C2VREN
C1VREN
CV
REF
Reference
EN
FVREN
0.6V
Fixed Ref
To Comparators
and ADC Module
To Comparators
and ADC Module
Note 1: Care should be taken to ensure V
REF remains
within the comparator common mode input range.
See Section 15.0 “Electrical Specifications” for
more detail.
4
15
0
1.2V
To ADC Module