UPD17708 datasheet(30/356 Pages) NEC

No. de pieza	UPD17708

Descripción Electrónicos	4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DEDICATED HARDWARE FOR DIGITAL TUNING SYSTEM

PDF	356 Pages

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Fabricante Electrónico	NEC [NEC]

Página de inicio	http://www.nec.com/

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30 / 356 page

µPD17704, 17705, 17707, 17708, 17709

3. ADDRESS STACK (ASK)

3.1 Outline of Address Stack

Figure 3-1 outlines the address stack.

The address stack consists of a stack pointer and address stack registers.

The address of an address stack register is specified by the stack pointer.

The address stack saves a return address when a subroutine call instruction is executed or when an interrupt

is accepted.

The address stack is also used when the table reference instruction is executed.

Figure 3-1. Outline of Address Stack

3.2 Address Stack Register (ASR)

Figure 3-2 shows the configuration of the address stack register.

The address stack register consists of sixteen 16-bit registers ASR0 through ASR15. Actually, however, it

consists of fifteen 16-bit registers (ASR0 through ASR14) because no register is allocated to ASR15.

The address stack saves a return address when a subroutine is called, when an interrupt is accepted, and

when the table reference instruction is executed.

Stack pointer

Return address

Address stack register

Address specification

UPD17708 Datasheet(PDF) 30 Page - NEC