PIC18F45J10 FAMILY
6.0
MEMORY ORGANIZATION
6.1
Program Memory Organization
There are two types of memory in PIC18 Enhanced
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
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 PIC18F24J10 and PIC18F44J10 each have
16 Kbytes of Flash memory and can store up to
8,192 single-word instructions. The PIC18F25J10 and
PIC18F45J10 each have 32 Kbytes of Flash memory
and can store up to 16,384 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 map for the PIC18F45J10 family
devices is shown in Figure 6-1.
FIGURE 6-1:
PROGRAM MEMORY MAP AND STACK FOR PIC18F45J10 FAMILY DEVICES
PC<20:0>
CALL,RCALL,RETURN
RETFIE,RETLW
Stack Level 1
•
•
•
21
Stack Level 31
Reset Vector
High-Priority Interrupt Vector
Low-Priority Interrupt Vector
On-Chip
Program Memory
On-Chip
Program Memory
0000h
0008h
0018h
PIC18FX4J10
7FF7h
8000h
PIC18FX5J10
Read ‘0’
Read ‘0’
1FFFFFh
200000h
©
2009 Microchip Technology Inc.
User Memory Space
3FF7h
4000h
DS39682E-page 51
MICROCHIP [ MICROCHIP TECHNOLOGY ]
