PIC18F87K90-E/PT Microchip Technology, PIC18F87K90-E/PT Datasheet - Page 404

• Manufacturer Part Number: PIC18F87K90-E/PT
• Description: 128kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm TR
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F87K90-E/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 24x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 80-TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC18F87K90 FAMILY
FIGURE 26-3:
26.5
In many applications, it is desirable to detect a drop
below, or rise above, a particular voltage threshold. For
example, the HLVD module could be periodically
enabled to detect Universal Serial Bus (USB) attach or
detach. This assumes the device is powered by a lower
voltage source than the USB 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,
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
(Interrupt Service Routine), which would allow the
application to perform “housekeeping tasks” and a
controlled shutdown before the device voltage exits the
valid operating range at T
cation a time window, represented by the difference
between T
DS39957D-page 404
A
, the HLVD logic generates an interrupt at time, T
CASE 1:
CASE 2:
Enable HLVD
Enable HLVD
Applications
A
and T
HLVDIF
HLVDIF
IRVST
IRVST
V
V
DD
DD
B
, to safely exit.
HIGH-VOLTAGE DETECT OPERATION (VDIRMAG =
Internal Reference is Stable
HLVDIF May Not be Set
B
. This would give the appli-
Figure 26-4
shows a
Internal Reference is Stable
T
T
IRVST
IRVST
A
.
HLVDIF Cleared in Software,
HLVDIF remains Set since HLVD Condition still Exists
FIGURE 26-4:
V
V
A
B
Legend:
HLVDIF Cleared in Software
HLVDIF Cleared in Software
V
V
 2009-2011 Microchip Technology Inc.
A
B
1
= HLVD trip point
= Minimum valid device
)
TYPICAL LOW-VOLTAGE
DETECT APPLICATION
operating voltage
Time
T
V
A
V
HLVD
HLVD
T
B