µPD61P24

5

3.

PROGRAM MEMORY (ROM) ……… 1002 STEPS

× 10 BITS

The program memory (ROM) is configured in 10 bits steps. It is addressed by the program counter.

Program and table data are stored in the program memory.

Figure 3-1. Program Memory Map

Test program

area

000H

0FFH

100H

1FFH

200H

2FFH

300H

3E9H

3EAH

3FFH

4.

DATA MEMORY (RAM) ……… 32 WORDS

× 5 BITS

The data memory is a RAM of 32 words

× 5 bits. The data memory stores processing data. In some cases, the

data memory is processed in 8-bit units. R0 may be used as the data pointer for the ROM.

After power application, the RAM will be undefined. The RAM retains the previous data on reset.

Figure 4-1. Data Memory Organization

1

R0

0

RF

RB

RC

SP–3

SP–2

SP–1

SP–0

..

.

..

.

Caution Avoid using the RAM areas RD, RE, and RF in a CALL routine as much as possible because these

areas are also used as stack memory areas (to prevent program hang-up in case the value of the

SP is destroyed due to some reason such as noise).

When using these RAM areas as general-purpose RAM areas, be sure to include stack pointer

checking in the main routine.