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Numéro de référence | UPB8238 | ||
Description | 8080A SYSTEM CONTROLLER AND BUS DRIVER | ||
Fabricant | NEC | ||
Logo | |||
1 Page
NEe Microcomputers, Inc.
fttIEC
Jl,PB8228
J.I PB8238
8080A SYSTEM CONTROLLER
AND BUS DRIVER
OESCR IPTION
The pPB8228/8238 is a single chip cOntroller and bus driver for 8080A based
systems. All the required interface signals rrecessary to connect RAM, ROM and
I/O components to a pPD8080A are generated.
The pPB8228/8238 provides a bi·directional three·state bus driver for high TTL
fan-out and isolation of the processor data bus from the system data bus for
increased noise immunity.
The system controller portion of the pPB8228/8238 consists of a status latch for
definition of processor machine cycles and a gating array to decode this information
for direct interface to system components. The controller can enable gating of a
multi·byte interrupt onto the data bus or can automatically insert a RESTART 7 Onto
the data bus without any additional components.
Two devices are provided:. the pPB8228 for small systems without tight write timing
constraints and the pPB8238 for larger systems.
FEATU RES
• System Controller for 8080A Systems
• Bi-Directional Data Bus for Processor Isolation
• 3.60V Output High Voltage for Direct Interface to 8080A Processor
•• Three State Outputs on System Data Bus
• Enables Use of Multi-Byte Interrupt Instructions
• Generates RST 7 Interrupt Instruction
• pPB8228 for Small Memory Systems
• pPB8238 for Large Memory Systems
• Reduces System Package Count
• Schottky Bipolar Technology
PIN CONFIGURATION
STSTB
HLDA
WR
DBIN
DB4
D4
DB7
D7
DB3
D3
DB2
D2
DBa
GND
NC: No Connection
Vee
I/OW
MEMW
I/OR
MEMR
INTA
BUSEN
DS
DBS
D5
DB5
D,
DB,
DO
PIN NAMES
07 - Do
DB7 DB
liaR
IIOW
MEMR
MEMW
DBIN
I'ITA
HLDA
WR
BUSEN
STSTB
Vec
GND
Data Bus (Processor Side)
Data Bus (System Si<!~
I/O Read
1/0 Write
Memory Read
Memory Write
OBI N (From ProcttliSOri
Interrupt Al:.knowledge
HLDA (From Processor)
WR (From Processorl
Bus Enabte Input
Status Strobe (From J.'PB8224)
+5V
OVohs
II
Rev/l
571
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Pages | Pages 6 | ||
Télécharger | [ UPB8238 ] |
No | Description détaillée | Fabricant |
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