Microchip Technology MA160014 Data Sheet

 2010-2012 Microchip Technology Inc.

DS41412F-page 69

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 buses; this allows for
concurrent 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 

. Data EEPROM is

discussed separately 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).

This family of devices contain the following:

• PIC18(L)F23K22, PIC18(L)F43K22: 8 Kbytes of 

Flash Memory, up to 4,096 single-word instructions

• PIC18(L)F24K22, PIC18(L)F44K22: 16 Kbytes of 

Flash Memory, up to 8,192 single-word instructions

• PIC18(L)F25K22, PIC18(L)F45K22: 32 Kbytes of 

Flash Memory, up to 16,384 single-word instruc-
tions

• PIC18(L)F26K22, PIC18(L)F46K22: 64 Kbytes of 

Flash Memory, up to 37,768 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 PIC18(L)F2X/4XK22
devices is shown in 

. Memory block details

are shown in