PIC18F87J90 Datasheet, PDF (65/450 Pages) Microchip Technology – 64/80-Pin, High-Performance Microcontrollers with LCD Driver and nanoWatt Technology

PIC18F87J90 FAMILY
6.0 MEMORY ORGANIZATION
There are two types of memory in PIC18 Flash
microcontroller devices:
• Program Memory
• Data RAM
As Harvard architecture devices, the data and program
memories use separate busses; this allows for
concurrent access of the two memory spaces.
Additional detailed information on the operation of the
Flash program memory is provided in Section 7.0
“Flash Program Memory”.
6.1 Program Memory Organization
PIC18 microcontrollers implement a 21-bit program
counter which is capable of addressing a 2-Mbyte
program memory space. Accessing a location between
the upper boundary of the physically implemented
memory and the 2-Mbyte address will return all ‘0’s (a
NOP instruction).
The entire PIC18F87J90 family offers a range of
on-chip Flash program memory sizes, from 64 Kbytes
(up to 16,384 single-word instructions) to 128 Kbytes
(65,536 single-word instructions). The program
memory maps for individual family members are shown
in Figure 6-1.
FIGURE 6-1:
MEMORY MAPS FOR PIC18F87J90 FAMILY DEVICES
CALL, CALLW, RCALL,
PC<20:0>
21
RETURN, RETFIE, RETLW,
ADDULNK, SUBULNK
Stack Level 1

Stack Level 31
PIC18FX6J90
On-Chip
Memory
PIC18FX7J90
On-Chip
Memory
000000h
Config. Words
00FFFFh
Unimplemented
Read as ‘0’
Config. Words
Unimplemented
Read as ‘0’
01FFFFh
Note:
1FFFFFh
Sizes of memory areas are not to scale. Sizes of program memory areas are enhanced to show detail.
 2010 Microchip Technology Inc.
DS39933D-page 65