MA180025 Microchip Technology, MA180025 Datasheet - Page 89

MODULE PLUG-IN PIC18F87J90 PIM

MA180025

Manufacturer Part Number
MA180025
Description
MODULE PLUG-IN PIC18F87J90 PIM
Manufacturer
Microchip Technology
Series
PIC®r
Datasheets

Specifications of MA180025

Accessory Type
Plug-In Module (PIM) - PIC18F87J90
Product
Microcontroller Modules
Silicon Manufacturer
Microchip
Core Architecture
PIC
Core Sub-architecture
PIC18
Silicon Core Number
PIC18F
Silicon Family Name
PIC18FxxJxx
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With/related Products
PICDEM LCD 2 Demonstration Board (DM163030)
For Use With
DM163030 - KIT DEV PICDEM LCD2
Lead Free Status / Rohs Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
MA180025
Manufacturer:
Microchip Technology
Quantity:
135
Part Number:
MA180025
Manufacturer:
MICROCHIP
Quantity:
12 000
7.0
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 64 bytes at a time or two bytes at a time. Pro-
gram memory is erased in blocks of 1024 bytes at a
time. A bulk erase operation may not be issued from
user code.
Writing or erasing program memory will cease
instruction fetches 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.
FIGURE 7-1:
 2010 Microchip Technology Inc.
Note 1:
TBLPTRU
FLASH PROGRAM MEMORY
Table Pointer
The Table Pointer register points to a byte in program memory.
TBLPTRH
TABLE READ OPERATION
(1)
TBLPTRL
Program Memory
(TBLPTR)
DD
Instruction: TBLRD*
Program Memory
PIC18F87J90 FAMILY
7.1
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)
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 the data RAM space.
Figure 7-1 shows the operation of a table read with
program memory and data RAM.
Table write operations store data from 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 7.5 “Writing
to Flash Program Memory”. Figure 7-2 shows the
operation of a table write with 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.
Table Reads and Table Writes
Table Latch (8-bit)
TABLAT
DS39933D-page 89

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