UPD75P3018A datasheet(16/66 Pages) RENESAS

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µPD75P3018A

Data Sheet U11917EJ2V1DS

4.2 Setting of Stack Bank Selection Register (SBS)

Use the stack bank selection register to switch between Mk I mode and Mk II mode. Figure 4-1 shows the format for doing

this.

The stack bank selection register is set using a 4-bit memory manipulation instruction. When using the Mk I mode, be

sure to initialize the stack bank selection register to 10XXBNote at the beginning of the program. When using the Mk II mode,

be sure to initialize it to 00XXBNote.

Note

Set the desired value for XX.

Figure 4-1. Format of Stack Bank Selection Register

Cautions 1. SBS3 is set to “1” after RESET input, and consequently the CPU operates in Mk I mode. When using

instructions for Mk II mode, set SBS3 to “0” and set Mk II mode before using the instructions.

2. When using Mk II mode, execute a subroutine call instruction and an interrupt instruction after

RESET input and after setting the stack bank selection register.

SBS3

SBS2

SBS1

SBS0

F84H

Address

SBS

Symbol

Stack area specification

Memory bank 0

Memory bank 1

Memory bank 2

Memory bank 3

Be sure to set bit 2 to 0.

Mk II mode

Mk I mode

Mode selection specification

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