PIC18F6490-E/PT Microchip Technology, PIC18F6490-E/PT Datasheet - Page 256

• 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 21-3:
21.5
In many applications, the ability to detect a drop below,
or rise above a particular threshold, is desirable. For
example, the HLVD module could be periodically
enabled to detect USB attach or detach. This assumes
the device is powered by a lower voltage source than
the Universal Serial Bus when detached. An attach
would indicate a high-voltage detect from, for example,
3.3V to 5V (the voltage on USB) and vice versa for a
detach. This feature could save a design a few extra
components and an attach signal (input pin).
For general battery applications, Figure 21-4 shows a
possible voltage curve. Over time, the device voltage
decreases. When the device voltage reaches voltage,
V
The interrupt could cause the execution of an ISR,
which would allow the application to perform “house-
keeping tasks” and perform a controlled shutdown
before the device voltage exits the valid operating
range at T
application a time window, represented by the
difference between T
DS39629C-page 254
A
, the HLVD logic generates an interrupt at time, T
CASE 1:
CASE 2:
Enable HLVD
Enable HLVD
Applications
B
HLVDIF
HLVDIF
. The HLVD, thus, would give the
IRVST
IRVST
V
V
DD
DD
A
HIGH-VOLTAGE DETECT OPERATION (VDIRMAG =
and T
HLVDIF may not be set
Internal Reference is stable
B
, to safely exit.
Internal Reference is stable
T
T
IRVST
IRVST
A
.
HLVDIF cleared in software,
HLVDIF remains set since HLVD condition still exists
FIGURE 21-4:
V
V
A
B
Legend:
HLVDIF cleared in software
V
V
A
B
1
= HLVD trip point
= Minimum valid device
)
TYPICAL LOW-VOLTAGE
DETECT APPLICATION
operating voltage
© 2007 Microchip Technology Inc.
Time
HLVDIF cleared in software
T
A
V
V
LVD
LVD
T
B