PIC18F4431-E/ML Microchip Technology, PIC18F4431-E/ML Datasheet - Page 85

• Manufacturer Part Number: PIC18F4431-E/ML
• Description: IC MCU FLASH 8KX16 44QFN
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4431-E/ML

• Core Processor: PIC
• Core Size: 8-Bit
• 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 Size: 16KB (8K x 16)
• 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: 44-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.0
The Flash program memory is readable, writable and
erasable during normal operation over the entire V
range.
A read from program memory is executed on one byte
at a time. A write to program memory is executed on
blocks of 8 bytes at a time. Program memory is erased
in blocks of 64 bytes at a time. A bulk erase operation
may not be issued from user code.
While writing or erasing program memory, instruction
fetches cease until the operation is complete. The
program memory cannot be accessed during the write
or erase, therefore, code cannot execute. An internal
programming timer terminates program memory writes
and erases.
A value written to program memory does not need to be
a valid instruction. Executing a program memory
location that forms an invalid instruction results in a
NOP.
8.1
In order to read and write program memory, there are
two operations that allow the processor to move bytes
between the program memory space and the data
RAM:
• Table Read (TBLRD)
• Table Write (TBLWT)
FIGURE 8-1:
 2010 Microchip Technology Inc.
Note 1: The Table Pointer points to a byte in program memory.
TBLPTRU
FLASH PROGRAM MEMORY
Table Reads and Table Writes
Table Pointer
TBLPTRH
TABLE READ OPERATION
(1)
TBLPTRL
Program Memory
(TBLPTR)
PIC18F2331/2431/4331/4431
DD
Instruction: TBLRD*
Program Memory
The program memory space is 16 bits wide, while the
data RAM space is 8 bits wide. Table reads and table
writes move data between these two memory spaces
through an 8-bit register (TABLAT).
Table read operations retrieve data from program
memory and place it into TABLAT in the data RAM
space.
with program memory and data RAM.
Table write operations store data from TABLAT in the
data memory space into holding registers in program
memory. The procedure to write the contents of the
holding registers into program memory is detailed in
Section 8.5 “Writing to Flash Program
Figure 8-2
program memory and data RAM.
Table operations work with byte entities. A table block
containing data, rather than program instructions, is not
required to be word-aligned. Therefore, a table block can
start and end at any byte address. If a table write is being
used to write executable code into program memory,
program instructions will need to be word-aligned,
(TBLPTRL<0> = 0).
Figure 8-1
shows the operation of a table write with
shows the operation of a table read
Table Latch (8-bit)
TABLAT
DS39616D-page 85
Memory”.