PIC18F4431-E/P Microchip Technology, PIC18F4431-E/P Datasheet - Page 82

• Manufacturer Part Number: PIC18F4431-E/P
• Description: IC MCU FLASH 8KX16 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4431-E/P

• Core Size: 8-Bit
• Program Memory Size: 16KB (8K 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 ~ 125°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• 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: + 125 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
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 9 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: DVA18XP400 - DEVICE ADAPTER 18F4220 PDIP 40LDACICE0206 - ADAPTER MPLABICE 40P 600 MIL
• Lead Free Status / Rohs Status: Details

PIC18F2331/2431/4331/4431
7.7
Data EEPROM memory has its own code-protect bits in
Configuration Words. External read and write opera-
tions are disabled if either of these mechanisms are
enabled.
The microcontroller itself can both read and write to the
internal data EEPROM, regardless of the state of the
code-protect Configuration bit. Refer to
“Special Features of the CPU”
information.
7.8
There are conditions when the device may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been implemented. On power-up, the WREN bit is
cleared. In addition, writes to the EEPROM memory
are blocked during the Power-up Timer period (T
Parameter 33).
The write/initiate sequence, and the WREN bit
together, help prevent an accidental write during
Brown-out Reset, power glitch or software malfunction.
EXAMPLE 7-3:
DS39616D-page 82
LOOP
Required
Sequence
Operation During Code-Protect
Protection Against Spurious Write
CLRF
BCF
BCF
BCF
BSF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BTFSC
BRA
INCFSZ EEADR, F
BRA
BCF
BSF
DATA EEPROM REFRESH ROUTINE
EEADR
EECON1, CFGS
EECON1, EEPGD
INTCON, GIE
EECON1, WREN
EECON1, RD
55h
EECON2
0AAh
EECON2
EECON1, WR
EECON1, WR
$-2
LOOP
EECON1, WREN
INTCON, GIE
for additional
Section 23.0
; Start at address 0
; Set for memory
; Set for Data EEPROM
; Disable interrupts
; Enable writes
; Loop to refresh array
; Read current address
;
; Write 55h
;
; Write 0AAh
; Set WR bit to begin write
; Wait for write to complete
; Increment address
; Not zero, do it again
; Disable writes
; Enable interrupts
PWRT
,
7.9
The data EEPROM is a high-endurance, byte-
addressable array that has been optimized for the
storage of frequently changing information (e.g.,
program variables or other data that are updated
often). Frequently changing values will typically be
updated more often than Specification D124. If this is
not the case, an array refresh must be performed. For
this reason, variables that change infrequently (such as
constants, IDs, calibration, etc.) should be stored in
Flash program memory.
A simple data EEPROM refresh routine is shown in
Example
Note:
Using the Data EEPROM
7-3.
If data EEPROM is only used to store con-
stants and/or data that changes rarely, an
array refresh is likely not required. See
Specification D124.
 2010 Microchip Technology Inc.