DP8228 DP8228M DP8238 DP8238M System Controller and Bus Driver
December 1988
DP8228 DP8228M DP8238 DP8238M
System Controller and Bus Driver
General Description
The DP8228 DP8228M DP8238 DP8238M are system
controller bus 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 input output 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
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Y
Y
Y
Y
Y
Y
Single chip system controller and bus driver for 8080A
Microcomputer Systems
Allows use of multibyte CALL instructions for Interrupt
Acknowledge
Provides user-selected single-level interrupt vector
(RST 7)
Provides isolation of data bus
Supports a wide variety of system bus structures
Reduces system component count
DP8238 DP8238M provides advanced Input Output
Write and Memory Write control signals for large sys-
tem timing control
8080A Microcomputer Family Block Diagram
TL F 6825 鈥?1
TRI-STATE is a registered trademark of National Semiconductor Corporation
C
1995 National Semiconductor Corporation
TL F 6825
RRD-B30M105 Printed in U S A
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