PIC16F688-I/STG Microchip Technology, PIC16F688-I/STG Datasheet - Page 65

• Manufacturer Part Number: PIC16F688-I/STG
• Description: IC PIC MCU FLASH 4KX14 14TSSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/STG

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Program Memory Size: 7KB (4K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 14-TSSOP
• For Use With: XLT14SS-1 - SOCKET TRANSITION 14DIP/14SSOPAC162061 - HEADER INTRFC MPLAB ICD2 20PINAC162056 - HEADER INTERFACE ICD2 16F688
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7.10
The Comparator Voltage Reference module provides
an internally generated voltage reference for the
comparators. The following features are available:
• Independent from Comparator operation
• Two 16-level voltage ranges
• Output clamped to V
• Ratiometric with V
The VRCON register (Figure 7-3) controls the Voltage
Reference module shown in Figure 7-8.
7.10.1
The comparator voltage reference is independent of
the comparator configuration. Setting the VREN bit of
the VRCON register will enable the voltage reference.
7.10.2
The
voltage levels in each range. Range selection is
controlled by the VRR bit of the VRCON register. The
16 levels are set with the VR<3:0> bits of the VRCON
register.
The CV
following equations:
REGISTER 7-3:
© 2009 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6
bit 5
bit 4
bit 3-0
R/W-0
VREN
CV
REF
Comparator Voltage Reference
REF
INDEPENDENT OPERATION
OUTPUT VOLTAGE SELECTION
voltage reference has 2 ranges with 16
output voltage is determined by the
VREN: CV
1 = CV
0 = CV
Unimplemented: Read as ‘0’
VRR: CV
1 = Low range
0 = High range
Unimplemented: Read as ‘0’
VR<3:0>: CV
When VRR = 1: CV
When VRR = 0: CV
DD
U-0
—
VRCON: VOLTAGE REFERENCE CONTROL REGISTER
SS
REF
REF
REF
REF
circuit powered on
circuit powered down, no I
Range Selection bit
REF
W = Writable bit
‘1’ = Bit is set
Enable bit
Value Selection bits (0 ≤ VR<3:0> ≤ 15)
R/W-0
VRR
REF
REF
= (VR<3:0>/24) * V
= V
DD
/4 + (VR<3:0>/32) * V
U-0
—
DD
drain and CV
DD
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R/W-0
EQUATION 7-1:
The full range of V
the construction of the module. See Figure 7-8.
7.10.3
The CV
power consumption by configuring VRCON as follows:
• VREN = 0
• VRR = 1
• VR<3:0> = 0000
This allows the comparator to detect a zero-crossing
while not consuming additional CV
7.10.4
The comparator voltage reference is V
therefore, the CV
V
Voltage Reference can be found in Section 14.0
“Electrical Specifications”.
VR3
DD
V
V
. The tested absolute accuracy of the Comparator
DD
RR
RR
REF
REF
=
=
CV
CV
0 (high range):
1 (low range):
= V
OUTPUT CLAMPED TO V
OUTPUT RATIOMETRIC TO VDD
output voltage can be set to Vss with no
REF
REF
R/W-0
SS
VR2
REF
.
=
=
SS
output changes with fluctuations in
(VR<3:0>/24)
(V
to V
CV
DD
DD
/4) +
x = Bit is unknown
REF
PIC16F688
cannot be realized due to
R/W-0
VR1
OUTPUT VOLTAGE
(VR<3:0> V
REF
×
DS41203E-page 63
V
DD
module current.
DD
SS
×
derived and
R/W-0
VR0
DD
/32)
bit 0