UPD17705 datasheet(91/356 Pages) NEC

Part #	UPD17705

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

PDF	356 Pages

Scroll/Zoom	100%

Manufacturer	NEC [NEC]

Direct Link	http://www.nec.com/

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91 / 356 page

µPD17704, 17705, 17707, 17708, 17709

10. DATA BUFFER STACK

10.1 Outline of Data Buffer Stack

Figure 10-1 outlines the data buffer stack.

As shown in the figure, the data buffer stack consists of a data buffer stack pointer and data buffer stack

registers.

The data buffer stack saves or restores the contents of the data buffer when the “PUT” or “GET” instruction

is executed.

Therefore, the contents of the data buffer can be saved by one instruction when an interrupt is accepted.

Figure 10-1. Outline of Data Buffer Stack

10.2 Data Buffer Stack Register

Figure 10-2 shows the configuration of the data buffer stack registers.

As shown in the figure, the data buffer stack registers consist of four 16-bit registers.

The contents of the data buffer are saved by executing the “PUT” instruction, and the saved data is restored

by executing the “GET” instruction.

The data buffer contents can be successively saved up to 4 levels.

Data buffer

stack pointer

DBF

Data buffer stack registers

Address specification

UPD17705 Datasheet(PDF) 91 Page - NEC