PIC18F23K20-E/MLQTP MICROCHIP [Microchip Technology], PIC18F23K20-E/MLQTP Datasheet - Page 65

• Manufacturer Part Number: PIC18F23K20-E/MLQTP
• Description: 28/40/44-Pin Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

5.0
There are three types of memory in PIC18 Enhanced
microcontroller devices:
• Program Memory
• Data RAM
• Data EEPROM
As Harvard architecture devices, the data and program
memories use separate busses; this allows for concur-
rent access of the two memory spaces. The data
EEPROM, for practical purposes, can be regarded as
a peripheral device, since it is addressed and accessed
through a set of control registers.
Additional detailed information on the operation of the
Flash program memory is provided in Section 6.0
“Flash Program Memory”. Data EEPROM is
discussed separately in Section 7.0 “Data EEPROM
Memory”.
FIGURE 5-1:
© 2007 Microchip Technology Inc.
MEMORY ORGANIZATION
Program Memory
PIC18F23K20/
43K20
CALL,RCALL,RETURN
RETFIE,RETLW
Read ‘0’
On-Chip
PROGRAM MEMORY MAP AND STACK FOR PIC18F2XK20/4XK20 DEVICES
1FFFh
2000h
Program Memory
PIC18F24K20/
44K20
Read ‘0’
On-Chip
High Priority Interrupt Vector
Low Priority Interrupt Vector
3FFFh
4000h
Stack Level 31
Stack Level 1
Advance Information
Reset Vector
PC<20:0>
•
•
•
Program Memory
PIC18F25K20/
45K20
On-Chip
Read ‘0’
5.1
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).
This family of devices contain the following:
• PIC18F23K20, PIC18F43K20: 8 Kbytes of Flash
• PIC18F24K20, PIC18F44K20: 16 Kbytes of Flash
• PIC18F25K20, PIC18F45K20: 32 Kbytes of Flash
• PIC18F26K20, PIC18F46K20: 64 Kbytes of Flash
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 PIC18F2XK20/4XK20
devices is shown in Figure 5-1. Memory block details
are shown in Figure 23-2.
PIC18F2XK20/4XK20
7FFFh
8000h
Memory, up to 4,096 single-word instructions
Memory, up to 8,192 single-word instructions
Memory, up to 16,384 single-word instructions
Memory, up to 37,768 single-word instructions
Program Memory Organization
Program Memory
PIC18F26K20/
46K20
21
On-Chip
Read ‘0’
10000h
FFFFh
0000h
0008h
0018h
1FFFFFh
200000h
DS41303B-page 63