PIC18F452-I/P Microchip Technology, PIC18F452-I/P Datasheet - Page 197

• Manufacturer Part Number: PIC18F452-I/P
• Description: IC MCU FLASH 16KX16 EE 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F452-I/P

• Program Memory Type: FLASH
• Program Memory Size: 32KB (16K x 16)
• Package / Case: 40-DIP (0.600", 15.24mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 34
• Eeprom Size: 256 x 8
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 1.5 KB
• Interface Type: MSSP/SPI/I2C/PSP/USART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 34
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 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, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Package: 40PDIP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 40 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCUACICE0206 - ADAPTER MPLABICE 40P 600 MIL
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: PIC18F452I/P; Q1176145

19.0
There are several features intended to maximize sys-
tem reliability, minimize cost through elimination of
external components, provide power saving Operating
modes and offer code protection. These are:
• OSC Selection
• RESET
• Interrupts
• Watchdog Timer (WDT)
• SLEEP
• Code Protection
• ID Locations
• In-Circuit Serial Programming
All PIC18FXX2 devices have a Watchdog Timer, which
is permanently enabled via the configuration bits or
software controlled. It runs off its own RC oscillator for
added reliability. There are two timers that offer neces-
sary delays on power-up. One is the Oscillator Start-up
Timer (OST), intended to keep the chip in RESET until
the crystal oscillator is stable. The other is the Power-
up Timer (PWRT), which provides a fixed delay on
power-up only, designed to keep the part in RESET
while the power supply stabilizes. With these two tim-
ers on-chip, most applications need no external
RESET circuitry.
SLEEP mode is designed to offer a very low current
Power-down mode. The user can wake-up from
SLEEP through external RESET, Watchdog Timer
Wake-up or through an interrupt. Several oscillator
options are also made available to allow the part to fit
the application. The RC oscillator option saves system
cost, while the LP crystal option saves power. A set of
configuration bits are used to select various options.
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
2002 Microchip Technology Inc.
SPECIAL FEATURES OF THE
CPU
19.1
The configuration bits can be programmed (read as '0'),
or left unprogrammed (read as '1'), to select various
device configurations. These bits are mapped starting
at program memory location 300000h.
The user will note that address 300000h is beyond the
user program memory space. In fact, it belongs to the
configuration memory space (300000h - 3FFFFFh),
which can only be accessed using Table Reads and
Table Writes.
Programming the configuration registers is done in a
manner similar to programming the FLASH memory
(see Section 5.5.1). The only difference is the configu-
ration registers are written a byte at a time. The
sequence of events for programming configuration
registers is:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. Re-enable interrupts.
Load table pointer with address of configuration
register being written.
Write a single byte using the TBLWT instruction.
Set EEPGD to point to program memory, set the
CFGS bit to access configuration registers, and
set WREN to enable byte writes.
Disable interrupts.
Write 55h to EECON2.
Write AAh to EECON2.
Set the WR bit. This will begin the write cycle.
CPU will stall for duration of write (approximately
2 ms using internal timer).
Execute a NOP.
Configuration Bits
PIC18FXX2
DS39564B-page 195