PIC18CXX2_13 Datasheet, PDF (35/304 Pages) Microchip Technology – High Performance Microcontrollers with 10-bit A/D

4.0 MEMORY ORGANIZATION
There are two memory blocks in Enhanced MCU
devices. These memory blocks are:
• Program Memory
• Data Memory
Program and data memory use separate buses so that
concurrent access can occur.
4.1 Program Memory Organization
A 21-bit program counter is capable of addressing the
2-Mbyte program memory space. Accessing a location
between the physically implemented memory and the
2-Mbyte address will cause a read of all ’0’s (a NOP
instruction).
PIC18C252 and PIC18C452 have 32 Kbytes of
EPROM, while PIC18C242 and PIC18C442 have
16 Kbytes of EPROM. This means that PIC18CX52
devices can store up to 16K of single word instructions,
and PIC18CX42 devices can store up to 8K of single
word instructions.
The RESET vector address is at 0000h and the inter-
rupt vector addresses are at 0008h and 0018h.
Figure 4-1 shows the Program Memory Map for
PIC18C242/442 devices and Figure 4-2 shows the
Program Memory Map for PIC18C252/452 devices.
PIC18CXX2
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DS39026D-page 35