EXTERNAL BUS
14-35
14
Systems with multiple I/O channels frequently use dual-ported memory to link several identical
I/O devices to the local bus, as in
Figure 14-19
. These systems are more complex, but performance
and flexibility improve because bus traffic is partitioned away from the i960 Jx processor’s local
bus. An example of such a system might be a network hub.
Figure 14-19. Generalized 80960Jx System with 80960 Local Bus
A more elaborate system would connect the 80960Jx’s bus to a backplane through bus interface
logic as shown in
Figure 14-20
. The backplane bus (or system bus) connects to multiple high
performance I/O devices (often with DMA) and large buffer memory for caching packets of data
from disk drives or LANs. Backplane buses can connect to other microprocessor local buses, too,
creating a loosely coupled multiprocessor system for resource sharing.
Figure 14-20. Generalized 80960Jx System with 80960 Local Bus and Backplane Bus
i960 Jx
Processor
80960 Local Bus
Base
I/O
Dual Port
Memory
High-Perf
I/O
Local
Memory
i960 Jx
Processor
Backplane Bus
Base
I/O
Local
Memory
Bus
Interface
High-Perf
I/O
Cache
Memory
80960 Local Bus
Summary of Contents for i960 Jx
Page 1: ...Release Date December 1997 Order Number 272483 002 i960 Jx Microprocessor Developer s Manual ...
Page 24: ......
Page 25: ...1 INTRODUCTION ...
Page 26: ......
Page 35: ...2 DATA TYPES AND MEMORY ADDRESSING MODES ...
Page 36: ......
Page 46: ......
Page 47: ...3 PROGRAMMING ENVIRONMENT ...
Page 48: ......
Page 73: ...4 CACHE AND ON CHIP DATA RAM ...
Page 74: ......
Page 85: ...5 INSTRUCTION SET OVERVIEW ...
Page 86: ......
Page 111: ...6 INSTRUCTION SET REFERENCE ...
Page 112: ......
Page 233: ...7 PROCEDURE CALLS ...
Page 234: ......
Page 256: ......
Page 257: ...8 FAULTS ...
Page 258: ......
Page 291: ...9 TRACING AND DEBUGGING ...
Page 292: ......
Page 309: ...10 TIMERS ...
Page 310: ......
Page 324: ......
Page 325: ...11 INTERRUPTS ...
Page 326: ......
Page 369: ...12 INITIALIZATION AND SYSTEM REQUIREMENTS ...
Page 370: ......
Page 412: ......
Page 413: ...13 MEMORY CONFIGURATION ...
Page 414: ......
Page 429: ...14 EXTERNAL BUS ...
Page 430: ......
Page 468: ......
Page 469: ...15 TEST FEATURES ...
Page 470: ......
Page 493: ...A CONSIDERATIONS FOR WRITING PORTABLE CODE ...
Page 494: ......
Page 502: ......
Page 503: ...B OPCODES AND EXECUTION TIMES ...
Page 504: ......
Page 515: ...C MACHINE LEVEL INSTRUCTION FORMATS ...
Page 516: ......
Page 523: ...D REGISTER AND DATA STRUCTURES ...
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Page 550: ......
Page 551: ...GLOSSARY ...
Page 552: ......
Page 561: ...INDEX ...
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