TLF6825

December 1988

DP8228DP8228MDP8238DP8238M

System Controller and Bus Driver

General Description

The DP8228DP8228M

DP8238DP8238M are system

controllerbus drivers contained in a standard 28-pin dual-

in-line package The chip which is fabricated using Schottky

Bipolar technology generates all the read and write control

signals required to directly interface the memory and input

output components of the 8080A microcomputer family The

chip also provides drive and isolation for the bidirectional

data bus of the 8080A microprocessor Data bus isolation

enables the use of slower memory and inputoutput compo-

nents in a system and provides for enhanced system noise

immunity

A user-selected signal-level interrupt vector (RST 7) is pro-

vided by the device for use in the interrupt structure of small

systems that need only one basic vector No additional

components (such as an interrupt instruction port) are re-

quired to use the single interrupt vector in these systems

The devices also generate an Interrupt Acknowledge (INTA)

control signal for each byte of a multibyte CALL instruction

when an interrupt is acknowledged by the 8080A This fea-

ture permits the use of a multilevel priority interrupt structure

in large interrupt-driven systems

Features

Y

Single chip system controller and bus driver for 8080A

Microcomputer Systems

Y

Allows use of multibyte CALL instructions for Interrupt

Acknowledge

Y

Provides

user-selected

single-level

interrupt

vector

(RST 7)

Y

Provides isolation of data bus

Y

Supports a wide variety of system bus structures

Y

Reduces system component count

Y

DP8238DP8238M

provides

advanced

InputOutput

Write and Memory Write control signals for large sys-

tem timing control

8080A Microcomputer Family Block Diagram

TLF6825 – 1

TRI-STATE

is a registered trademark of National Semiconductor Corporation

C1995 National Semiconductor Corporation

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