PIC18F24 MICROCHIP [Microchip Technology], PIC18F24 Datasheet - Page 39

• Manufacturer Part Number: PIC18F24
• Description: 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

4.0
There are three memory blocks in Enhanced MCU
devices. These memory blocks are:
• Enhanced Flash Program Memory
• Data Memory
• EEPROM Data Memory
Data and program memory use separate busses,
which allows concurrent access of these blocks.
Additional detailed information on data EEPROM and
Flash program memory is provided in Section 5.0
“Data EEPROM Memory” and Section 6.0 “Flash
Program Memory”, respectively.
4.1
The PIC18F258/458 devices have a 21-bit program
counter that is capable of addressing a 2-Mbyte
program memory space.
The Reset vector address is at 0000h and the interrupt
vector addresses are at 0008h and 0018h.
FIGURE 4-1:
 2004 Microchip Technology Inc.
CALL,RCALL,RETURN
RETFIE,RETLW
MEMORY ORGANIZATION
Program Memory Organization
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector
Program Memory
Stack Level 31
Stack Level 1
Reset Vector
PC<20:0>
Read ‘0’
On-Chip
PROGRAM MEMORY MAP
AND STACK FOR
PIC18F248/448
21
0000h
0018h
3FFFh
4000h
1FFFFFh
200000h
Figure 4-1 shows the diagram for program memory
map and stack for the PIC18F248 and PIC18F448.
Figure 4-2 shows the diagram for the program memory
map and stack for the PIC18F258 and PIC18F458.
4.1.1
The PIC18F258 and the PIC18F458 have 32 Kbytes of
internal Enhanced Flash program memory. This means
that the PIC18F258 and the PIC18F458 can store up to
16K of single-word instructions. The PIC18F248 and
PIC18F448 have 16 Kbytes of Enhanced Flash
program memory. This translates into 8192 single-word
instructions, which can be stored in the program
memory. Accessing a location between the physically
implemented memory and the 2-Mbyte address will
cause a read of all ‘0’s (a NOP instruction).
FIGURE 4-2:
CALL,RCALL,RETURN
RETFIE,RETLW
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector
INTERNAL PROGRAM MEMORY
OPERATION
Program Memory
Stack Level 31
Stack Level 1
Reset Vector
PC<20:0>
Read ‘0’
On-Chip
PROGRAM MEMORY MAP
AND STACK FOR
PIC18F258/458
PIC18FXX8
21
DS41159D-page 37
0000h
0018h
7FFFh
8000h
1FFFFFh
200000h