PIC18F2550-I/SO Microchip Technology, PIC18F2550-I/SO Datasheet - Page 283

• Manufacturer Part Number: PIC18F2550-I/SO
• Description: IC PIC MCU FLASH 16KX16 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2550-I/SO

• Program Memory Type: FLASH
• Program Memory Size: 32KB (16K x 16)
• Package / Case: 28-SOIC (7.5mm Width)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 24
• Eeprom Size: 256 x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI/I2C/EAUSART
• Maximum Clock Frequency: 48 MHz
• Number Of Programmable I/os: 24
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DM163025, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10-ch x 10-bit
• Package: 28SOIC W
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 48 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28SO-1 - SOCKET TRANSITION 28SOIC 300MILI3-DB18F4550 - BOARD DAUGHTER ICEPIC3DM163025 - PIC DEM FULL SPEED USB DEMO BRD
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

23.0
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 23-1.
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
23.1
The voltage reference module is controlled through the
CVRCON register (Register 23-1). The comparator
voltage reference provides two ranges of output
voltage, each with 16 distinct levels. The range to be
REGISTER 23-1:
© 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
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 TRISA<2> 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
CVR3:CVR0: Comparator V
When CVRR = 1:
CV
When CVRR = 0:
CV
/V
CVROE
SS
REF
REF
R/W-0
or an external voltage reference.
CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
= ((CVR3:CVR0)/24) • (CV
= (CV
REF
REF
REF
REF
(1)
circuit powered on
circuit powered down
voltage level is also output on the RA2/AN2/V
voltage is disconnected from the RA2/AN2/V
RSRC
RSRC
W = Writable bit
‘1’ = Bit is set
R/W-0
CVRR
RSRC
/4) + ((CVR3:CVR0)/32) • (CV
to 0.75 CV
REF
REF
REF
, with CV
Range Selection bit
Source Selection bit
Output Enable bit
REF
PIC18F2455/2550/4455/4550
RSRC
CVRSS
R/W-0
RSRC
Value Selection bits (0 ≤ (CVR3:CVR0) ≤ 15)
, with CV
RSRC
/24 step size (low range)
RSRC
RSRC
)
U = Unimplemented bit, read as ‘0’
RSRC
‘0’ = Bit is cleared
= (V
= V
(1)
R/W-0
CVR3
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:
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
Characteristics”).
output (see Table 28-3 in Section 28.0 “Electrical
DD
REF
/32 step size (high range)
REF
RSRC
– V
If CVRR = 1:
CV
If CVRR = 0:
CV
CV
+) – (V
- that are multiplexed with RA2 and RA3. The
)
SS
REF
REF
RSRC
selected
REF
REF
= ((CVR3:CVR0)/24) x CV
REF
= (CV
)
-/CV
DD
R/W-0
-/CV
CVR2
-)
and V
REF
RSRC
REF
by
pin
pin
SS
/4) + (((CVR3:CVR0)/32) x
the
, or the external V
x = Bit is unknown
R/W-0
CV
CVR1
REF
DS39632E-page 281
RSRC
Selection
R/W-0
CVR0
REF
+ and
bit 0
REF
bits