PIC18F6490-E/PT Microchip Technology, PIC18F6490-E/PT Datasheet - Page 250

• Manufacturer Part Number: PIC18F6490-E/PT
• Description: IC PIC MCU FLASH 16KX16 64TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F6490-E/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, LCD, POR, PWM, WDT
• Number Of I /o: 50
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 64-TFQFP
• For Use With: DM163028 - BOARD DEMO PICDEM LCD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

PIC18F6390/6490/8390/8490
FIGURE 20-1:
20.2
The full range of voltage reference cannot be realized
due to the construction of the module. The transistors
on the top and bottom of the resistor ladder network
(Figure 20-1) keep CV
ence source rails. The voltage reference is derived
from the reference source; therefore, the CV
changes with fluctuations in that source. The tested
absolute accuracy of the voltage reference can be
found in Section 26.0 “Electrical Characteristics”.
20.3
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the CVRCON register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
DS39629C-page 248
Voltage Reference Accuracy/Error
Operation During Sleep
CVRR
V
V
CVREN
V
REF
DD
REF
REF
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
+
-
from approaching the refer-
CVRSS = 0
CVRSS = 1
CVRSS = 1
CVRSS = 0
16 Steps
REF
output
8R
R
R
R
R
R
R
R
clearing bit, CVREN (CVRCON<7>). This Reset also dis-
20.4
A device Reset disables the voltage reference by
connects the reference from the RA2 pin by clearing bit,
CVROE (CVRCON<6>), and selects the high-voltage
range by clearing bit, CVRR (CVRCON<5>). The CVR
value select bits are also cleared.
20.5
The voltage reference module operates independently
of the comparator module. The output of the reference
generator may be connected to the RF5 pin if the
TRISF<5> bit and the CVROE bit are both set.
Enabling the voltage reference output onto the RF5 pin,
with an input signal present, will increase current
consumption. Connecting RF5 as a digital output with
CVRSS
consumption.
The RF5 pin can be used as a simple D/A output with
limited drive capability. Due to the limited current drive
capability, a buffer must be used on the voltage
reference output for external connections to V
Figure 20-2 shows an example buffering technique.
8R
Effects of a Reset
Connection Considerations
CVR3:CVR0
enabled
will
© 2007 Microchip Technology Inc.
also
CV
REF
increase
current
REF
.