PIC18F4220-I/PT Microchip Technology, PIC18F4220-I/PT Datasheet - Page 236

• Manufacturer Part Number: PIC18F4220-I/PT
• Description: IC MCU FLASH 2KX16 A/D 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4220-I/PT

• Core Size: 8-Bit
• Program Memory Size: 4KB (2K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 13x10b
• 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: 512Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Core: PIC
• Processor Series: PIC18F
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 40 MHz
• Data Ram Size: 512 B
• Data Rom Size: 256 B
• On-chip Adc: Yes
• Number Of Programmable I/os: 36
• Number Of Timers: 2 x 8 bit
• Operating Supply Voltage: 2 V to 5.5 V
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 13
• Height: 1 mm
• Interface Type: SPI, I2C, USART
• Length: 10 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.2 V
• Width: 10 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44PT3 - SOCKET TRAN ICE 44MQFP/TQFPAC164305 - MODULE SKT FOR PM3 44TQFP444-1001 - DEMO BOARD FOR PICMICRO MCUAC164020 - MODULE SKT PROMATEII 44TQFP
• Lead Free Status / Rohs Status: Details

PIC18F2220/2320/4220/4320
22.2
Depending on the power source for the device voltage,
the voltage normally decreases relatively slowly. This
means that the LVD module does not need to be
constantly operating. To decrease the current require-
ments, the LVD circuitry only needs to be enabled for
short periods where the voltage is checked. After doing
the check, the LVD module may be disabled.
Each time that the LVD module is enabled, the circuitry
requires some time to stabilize. After the circuitry has
stabilized, all status flags may be cleared. The module
will then indicate the proper state of the system.
FIGURE 22-4:
DS39599G-page 234
Internally Generated
Internally Generated
Reference Stable
Reference Stable
CASE 1:
CASE 2:
Operation
Enable LVD
Enable LVD
LVDIF
LVDIF
V
V
DD
DD
LOW-VOLTAGE DETECT WAVEFORMS
T
T
IRVST
IRVST
LVDIF may not be set
The following steps are needed to set up the LVD
module:
1.
2.
3.
4.
5.
6.
Figure 22-4 shows typical waveforms that the LVD
module may be used to detect.
LVDIF cleared in software,
LVDIF remains set since LVD condition still exists
Write the value to the LVDL3:LVDL0 bits
(LVDCON register) which selects the desired
LVD trip point.
Ensure that LVD interrupts are disabled (the
LVDIE bit is cleared or the GIE bit is cleared).
Enable the LVD module (set the LVDEN bit in
the LVDCON register).
Wait for the LVD module to stabilize (the IRVST
bit to become set).
Clear the LVD interrupt flag, which may have
falsely become set, until the LVD module has
stabilized (clear the LVDIF bit).
Enable the LVD interrupt (set the LVDIE and the
GIE bits).
LVDIF cleared in software
© 2007 Microchip Technology Inc.
LVDIF cleared in software
V
V
LVD
LVD