PIC18F87J72-I/PT Microchip Technology, PIC18F87J72-I/PT Datasheet - Page 299

• Manufacturer Part Number: PIC18F87J72-I/PT
• Description: IC PIC MCU 8BIT 14KB FLSH 80TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F87J72-I/PT

• Program Memory Type: FLASH
• Program Memory Size: 128KB (64K x 16)
• Package / Case: 80-TQFP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, LVD, POR, PWM, WDT
• Number Of I /o: 51
• Ram Size: 3.8K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 3.6 V
• Data Converters: A/D 12x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART, SPI, I2C
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 51
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 14
• Controller Family/series: PIC18F
• No. Of I/o's: 51
• Ram Memory Size: 3923Byte
• Cpu Speed: 48MHz
• No. Of Timers: 4
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

24.0
The comparator voltage reference is a 16-tap resistor
ladder network that provides a selectable reference
voltage. Although its primary purpose is to provide a
reference for the analog comparators, it may also be
used independently of them.
A block diagram of the module is shown in Figure 24-1.
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
24.1
The comparator voltage reference module is controlled
through the CVRCON register (Register 24-1). The
comparator voltage reference provides two ranges of
output voltage, each with 16 distinct levels.
REGISTER 24-1:
 2010 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6
bit 5
bit 4
bit 3-0
Note 1:
CVREN
R/W-0
REF
COMPARATOR VOLTAGE
REFERENCE MODULE
Configuring the Comparator
Voltage Reference
values and has a power-down function to
CVROE overrides the TRISF<5> bit setting.
DD
CVREN: Comparator Voltage Reference Enable bit
1 = CV
0 = CV
CVROE: Comparator V
1 = CV
0 = CV
CVRR: Comparator V
1 = 0 to 0.667 CV
0 = 0.25 CV
CVRSS: Comparator V
1 = Comparator reference source, CV
0 = Comparator reference source, CV
CVR<3:0>: Comparator V
When CVRR = 1:
CV
When CVRR = 0:
CV
CVROE
/V
REF
REF
R/W-0
SS
or an external voltage reference.
CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
= ((CVR<3:0>)/24)  (CV
= (CV
REF
REF
REF
REF
(1)
voltage is disconnected from the RF5/AN10/CV
circuit powered on
circuit powered down
voltage level is also output on the RF5/AN10/CV
RSRC
RSRC
W = Writable bit
‘1’ = Bit is set
R/W-0
CVRR
/4) + ((CVR<3:0>)/32)  (CV
RSRC
to 0.75 CV
REF
REF
REF
, with CV
Range Selection bit
REF
Source Selection bit
Output Enable bit
RSRC
Value Selection bits (0  (CVR<3:0>)  15)
RSRC
CVRSS
RSRC
R/W-0
, with CV
Preliminary
)
/24 step size (low range)
RSRC
RSRC
RSRC
= (V
= V
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
(1)
PIC18F87J72 FAMILY
RSRC
R/W-0
DD
CVR3
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 selected by the CV
Selection bits (CVR<3:0>), with one range offering finer
resolution. The equations used to calculate the output
of the comparator voltage reference are as follows:
The comparator reference supply voltage can come
from either V
V
voltage source is selected by the CVRSS bit
(CVRCON<4>).
The settling time of the comparator voltage reference
must be considered when changing the CV
output (see Table 29-3 in Section 29.0 “Electrical
Characteristics”).
/32 step size (high range)
REF
REF
– V
)
If CVRR = 1:
CV
If CVRR = 0:
CV
+) – (V
- that are multiplexed with RA2 and RA3. The
SS
REF
REF
= (CV
REF
= ((CVR<3:0>)/24) x (CV
REF
REF
DD
-)
R/W-0
CVR2
/SEG23/C1INB pin
/SEG23/C1INB pin
RSRC
and V
/4) + ((CVR<3:0>)/32) x (CV
SS
, or the external V
x = Bit is unknown
R/W-0
CVR1
DS39979A-page 299
RSRC
)
R/W-0
CVR0
REF
+ and
RSRC
bit 0
REF
REF
)