PIC16F684-I/SLG Microchip, PIC16F684-I/SLG Datasheet - Page 62

• Manufacturer Part Number: PIC16F684-I/SLG
• Description: pic, flash, Microcontrollers, Microprocessors, Semiconductors and Actives, ic, mcu
• Manufacturer: Microchip

PIC16F684
8.6
The comparator module also allows the selection of an
internally generated voltage reference for one of the
comparator inputs. The VRCON register (Register 8-3)
controls the voltage reference module shown in
Figure 8-6.
8.6.1
The voltage reference can output 32 distinct voltage
levels, 16 in a high range and 16 in a low range.
The following equation determines the output voltages:
EQUATION 8-1:
FIGURE 8-6:
DS41202C-page 60
VRR = 1 (low range): CV
VRR = 0 (high range):
V
DD
Comparator
CV
Comparator Reference
CV
REF
CONFIGURING THE VOLTAGE
REFERENCE
REF
VREN
Input
= (V
to
DD
/4) + (VR3:VR0
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
REF
VR3:VR0
16-1 Analog
= (VR3:VR0/24)
8R
MUX
X
V
DD
R
/32)
VREN
VR3:VR0 = ‘0000’
VRR
X
V
DD
Preliminary
R
16 Stages
8.6.2
The full range of V
the construction of the module. The transistors on the
top and bottom of the resistor ladder network
(Figure 8-6) keep CV
V
clearing the VREN bit (VRCON<7>). When disabled,
the reference voltage is V
and the VRR (VRCON<5>) bit is set. This allows the
comparators to detect a zero-crossing and not
consume CV
The voltage reference is V
CV
tested absolute accuracy of the comparator voltage
Reference can be found in Section 15.0 “Electrical
Specifications”.
DD
REF
. The exception is when the module is disabled by
R
output changes with fluctuations in V
VOLTAGE REFERENCE
ACCURACY/ERROR
REF
R
module current.
SS
to V
REF
 2004 Microchip Technology Inc.
DD
DD
SS
from approaching V
8R
cannot be realized due to
derived and therefore, the
when VR<3:0> is ‘0000’
VRR
DD
SS
. The
or