PIC18F25J50 MICROCHIP [Microchip Technology], PIC18F25J50 Datasheet - Page 399

• Manufacturer Part Number: PIC18F25J50
• Description: 28/44-Pin, Low-Power, High-Performance USB Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

FIGURE 25-3:
25.5
In many applications, it is desirable to have the ability to
detect a drop below, or rise above, a particular threshold.
For example, the HLVD module could be enabled
periodically to detect Universal Serial Bus (USB) attach
or detach.
For general battery applications,
a possible voltage curve.
Over time, the device voltage decreases. When the
device voltage reaches voltage, V
generates an interrupt at time, T
cause the execution of an ISR, which would allow the
application to perform “housekeeping tasks” and
perform a controlled shutdown before the device
voltage exits the valid operating range at T
Thus, the HLVD would give the application a time
window, represented by the difference between T
T
 2011 Microchip Technology Inc.
B
, to safely exit.
CASE 1:
CASE 2:
Enable HLVD
Enable HLVD
Applications
HLVDIF
HLVDIF
IRVST
IRVST
V
V
DD
DD
HIGH-VOLTAGE DETECT OPERATION (VDIRMAG =
HLVDIF may not be set
Internal Reference is stable
A
Figure 25-4
. The interrupt could
A
, the HLVD logic
B
.
provides
A
Internal Reference is stable
and
T
T
IRVST
IRVST
PIC18F46J50 FAMILY
HLVDIF cleared in software,
HLVDIF remains set since HLVD condition still exists
FIGURE 25-4:
V
V
A
B
Legend:
HLVDIF cleared in software
V
V
1
A
B
)
= HLVD trip point
= Minimum valid device
TYPICAL HIGH/
LOW-VOLTAGE DETECT
APPLICATION
operating voltage
Time
HLVDIF cleared in software
T
A
V
V
DS39931D-page 399
HLVD
HLVD
T
B