PIC18F4585-H/P Microchip Technology, PIC18F4585-H/P Datasheet - Page 265

• Manufacturer Part Number: PIC18F4585-H/P
• Description: IC MCU 8BIT 48KB FLASH 40PDIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4585-H/P

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Size: 48KB (24K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.25K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

21.0
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 is of the module shown in Figure 21-1.
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
21.1
The voltage reference module is controlled through the
CVRCON register (Register 21-1). The comparator
voltage reference provides two ranges of output
voltage, each with 16 distinct levels. The range to be
REGISTER 21-1:
© 2007 Microchip Technology Inc.
REF
COMPARATOR VOLTAGE
REFERENCE MODULE
Configuring the Comparator
Voltage Reference
values and has a power-down function to
bit 7
bit 6
bit 5
bit 4
bit 3-0
DD
/V
SS
or an external voltage reference.
CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
bit 7
Legend:
R = Readable bit
-n = Value at POR
CVREN: Comparator Voltage Reference Enable bit
1 = CV
0 = CV
CVROE: Comparator V
1 = CV
0 = CV
CVRR: Comparator V
1 = 0.00 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
CVREN
R/W-0
Note 1: CVROE overrides the TRISA<0> bit setting. If enabled for output, RA2 must also
REF
REF
REF
REF
REF
REF
= ((CVR3:CVR0)/24) • (CV
= (CV
circuit powered on
circuit powered down
voltage level is also output on the RA0/AN0/CV
voltage is disconnected from the RA0/AN0/CV
CVROE
be configured as an input by setting TRISA<2> to ‘1’.
RSRC
RSRC
RSRC
R/W-0
to 0.75 CV
to 0.75 CV
/4) + ((CVR3:CVR0)/32) • (CV
(1)
PIC18F2585/2680/4585/4680
REF
REF
REF
R/W-0
CVRR
Range Selection bit
Preliminary
Source Selection bit
Output Enable bit
W = Writable bit
‘1’ = Bit is set
REF
RSRC
RSRC
Value Selection bits (0 ≤ (CVR3:CVR0) ≤ 15)
, with CV
, with CV
RSRC
CVRSS
R/W-0
RSRC
RSRC
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
(see
Characteristics”).
)
REF
RSRC
RSRC
= (V
= V
If CVRR = 1:
CV
If CVRR = 0:
CV
CV
- that are multiplexed with RA2 and RA3. The
(1)
REF
REF
RSRC
Table 27-3
DD
selected
/24 step size
/32 step size
REF
RSRC
R/W-0
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
CVR3
– V
= ((CVR3:CVR0)/24) x CV
+) – (V
= (CV
)
DD
)
SS
and V
DD
REF
REF
by
REF
x 1/4) + (((CVR3:CVR0)/32) x
in
R/W-0
CVR2
pin
-)
SS
pin
the
, or the external V
Section 27.0
CV
x = Bit is unknown
REF
R/W-0
CVR1
DS39625C-page 263
RSRC
Selection
“Electrical
REF
REF
R/W-0
CVR0
output
+ and
bit 0
bits