PIC18F4331-I/PT Microchip Technology, PIC18F4331-I/PT Datasheet - Page 265

• Manufacturer Part Number: PIC18F4331-I/PT
• Description: IC PIC MCU FLASH 4KX16 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4331-I/PT

• Core Size: 8-Bit
• Program Memory Size: 8KB (4K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, Power Control PWM, QEI, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 9x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Controller Family/series: PIC18
• No. Of I/o's: 36
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 768Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: EUSART, I2C, SPI, SSP
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 36
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 9 bit
• Package: 44TQFP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 40 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44PT3 - SOCKET TRAN ICE 44MQFP/TQFPI3-DB18F4431 - BOARD DAUGHTER ICEPIC3AC164305 - MODULE SKT FOR PM3 44TQFP444-1001 - DEMO BOARD FOR PICMICRO MCUAC164020 - MODULE SKT PROMATEII 44TQFP
• Lead Free Status / Rohs Status: Details
• Other names: PIC18F4331-I/PTR; PIC18F4331-I/PTR

21.0
In many applications, the ability to determine if the
device voltage (V
is a desirable feature. A window of operation for the
application can be created, where the application
software can do “housekeeping tasks” before the
device voltage exits the valid operating range. This can
be done using the Low-Voltage Detect module (LVD).
This module is a software programmable circuitry,
where a device voltage trip point can be specified.
When the voltage of the device becomes lower than the
specified point, an interrupt flag is set. If the interrupt is
enabled, the program execution will branch to the
interrupt vector address and the software can then
respond to that interrupt source.
The Low-Voltage Detect circuitry is completely under
software control. This allows the circuitry to be turned
off by the software, which minimizes the current
consumption for the device.
Figure 21-1 shows a possible application voltage curve
(typically for batteries). Over time, the device voltage
decreases. When the device voltage equals voltage V
the LVD logic generates an interrupt. This occurs at
time T
FIGURE 21-1:
© 2007 Microchip Technology Inc.
A
. The application software then has the time,
LOW-VOLTAGE DETECT
V
V
A
B
DD
) is below a specified voltage level
TYPICAL LOW-VOLTAGE DETECT APPLICATION
Time
T
A
PIC18F2331/2431/4331/4431
T
B
Preliminary
A
,
until the device voltage is no longer in valid operating
range, to shut down the system. Voltage point V
minimum valid operating voltage specification. This
occurs at time T
time for shutdown.
The block diagram for the LVD module is shown in
Figure 21-2. A comparator uses an internally gener-
ated reference voltage as the set point. When the
selected tap output of the device voltage crosses the
set point (is lower than), the LVDIF bit is set.
Each node in the resistor divider represents a “trip
point” voltage. The “trip point” voltage is the minimum
supply voltage level at which the device can operate
before the LVD module asserts an interrupt. When the
supply voltage is equal to the trip point, the voltage
tapped off of the resistor array is equal to the 1.2V
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal setting the LVDIF bit. This voltage is
software programmable to any one of 16 values (see
Figure 21-2). The trip point is selected by programming
the LVDL3:LVDL0 bits (LVDCON<3:0>).
Legend:
B
. The difference, T
V
V
A
B
= LVD trip point
= Minimum valid device
operating voltage
DS39616C-page 263
B
– T
A
, is the total
B
is the