18

MB89820 Series

s CPU CORE

1. Memory Space

The microcontrollers of the MB89820 series offer a memory space of 64 Kbytes for storing all of I/O, data, and

program areas. The I/O area is located at the lowest address. The data area is provided immediately above the

I/O area. The data area can be divided into register, stack, and direct areas according to the application. The

program area is located at exactly the opposite end, that is, near the highest address. Provide the tables of

interrupt reset vectors and vector call instructions toward the highest address within the program area. The

memory space of the MB89820 series is structured as illustrated below.

ROM

4 KB

RAM

Register

I/O

MB89821

Unused

Vacancy

MB89823

MB89P825

MB89PV820

ROM

8 KB

RAM

Register

I/O

Unused

PROM

16 KB

RAM

Register

I/O

Unused

External ROM

32 KB

RAM

Register

I/O

Unused

192 B

256 B

256 B

1 KB

Memory Space