PIC18F6390 Datasheet, PDF (67/412 Pages) Microchip Technology – 64/80-Pin Flash Microcontrollers with LCD Driver and nanoWatt Technology

PIC18F6390/6490/8390/8490
5.0 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 6.0
“Flash Program Memory”.
5.1 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 PIC18FX390 have 8 Kbytes of Flash memory and
can store up to 4,096 single-word instructions and
PIC18FX490 have 16 Kbytes of Flash memory and can
store up to 8,192 single-word instructions.
PIC18 devices have two interrupt vectors. The Reset
vector address is at 0000h and the interrupt vector
addresses are at 0008h and 0018h.
The
program
memory
maps
for
PIC18F6390/6490/8390/8490 devices are shown in
Figure 5-1.
FIGURE 5-1:
PROGRAM MEMORY MAP AND STACK FOR PIC18F6390/6490/8390/8490 DEVICES
PIC18F6390/8390
PC<20:0>
CALL,RCALL,RETURN
21
RETFIE,RETLW
Stack Level 1
•
•
•
Stack Level 31
Reset Vector
0000h
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector 0018h
On-Chip
Program Memory
1FFFh
2000h
PIC18F6490/8490
PC<20:0>
CALL,RCALL,RETURN
21
RETFIE,RETLW
Stack Level 1
•
•
•
Stack Level 31
Reset Vector
0000h
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector 0018h
On-Chip
Program Memory
3FFFh
4000h
Read ‘0’
Read ‘0’
1FFFFFh
 2004 Microchip Technology Inc.
Preliminary
1FFFFFh
DS39629B-page 65