195:-inspired "super Z80" that would run existing, and larger, programs at considerably higher speeds. However the address and data buses were multiplexed and the chip was, also in other respects, somewhat complicated to program and interface to. Calculation of exact execution times was also very much harder to do than for the Z80. Moreover, the plain Z80 were good enough for most applications at the time so the extra computing power was, in many cases, not worth the added complexity. Bad marketing seems to have hurt the product as well.
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232:(introduced 2001) has been both commercially successful and won engineering awards. Unlike the Z800, Z280, and Z380, the eZ80 does not introduce many new instructions or addressing modes, in comparison to the original Z80, but instead primarily extends the 16-bit registers of the Z80 to 24 bits wide. This enables it to reach 256 times as much memory, and adds a fully pipelined execution unit that executes Z80 opcodes 4× as fast as the original.
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versatile accumulators. In addition to the register operands possible in the Z80, they could be used with immediate data, direct address, register indirect, or indexed operands, even program counter-relative. Eight-bit operations had even more possibilities, including stack pointer-relative addressing and a choice of 8-bit or 16-bits immediate offsets.
65:, in that the Z800 was intended to be Z80 compatible, while the Z8000 was only Z80-like and did not offer any direct compatibility. Zilog sought to rectify the lack of Z80 compatibility exhibited by the Z8000 when introducing the Z800, seeking to offer Z80 binary compatibility with an eightfold performance increase over the Z80, mirroring plans by
94:
controller and clock, but added 256 bytes of RAM that could be used either as "scratchpad" RAM, or as a cache. When used in cache mode the programmer could configure it as a data or instruction cache, or both, and the internal memory controller then used it to reduce access to (slower) external memory.
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set but the registers and instructions were significantly orthogonalized in order to make them more general-purpose and powerful. Many new 8-bit and 16-bit operations were added, and the HL, IX, and IY registers were upgraded from their rather limited possibilities as accumulators in the Z80 to more
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The address bus was expanded to 24-bits to address 16 MB of memory. The chip was offered with either a 19-bit external bus for 512kB RAM, or a full 24-bit bus for 16MB RAM, the advantage to the smaller bus was a smaller 40-pin package. Like the Z80 before it, the Z800 retained the internal DRAM
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Another change was the addition of an optional 16-bit data bus, which doubled the rate at which it could access memory if set up properly. Combined with the two address bus sizes this meant that the chip was offered in a total of four versions:
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There were also ambitious provisions for multiprocessing and either loosely or tightly coupled slave processors, with or without shared global memory. This was known as the
202:, as a less ambitious Z80 derivative. It had great success, probably because it is almost as simple to program and interface to as the original Z80.
50:
and the Z800 never entered mass production. After more than five years had elapsed since it was originally introduced, the effort was redubbed the
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43:(MMU) to provide a 16 MB address range. It also added a huge number of new more orthogonal instructions and addressing modes.
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in 1986. An actual product, the Z280 would ship in 1987 with almost the same design as the Z800, but this time implemented in
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225:(introduced 1994) was a commercial disappointment except for some specific telecom applications. On the other hand, the fast
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and meant to be released in 1985. It was instruction compatible with their existing
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218:) and Zilog Z182 other attempts were made to extend the Z80 architecture, the
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Z800 MPU Family
Preliminary Product Specification (00-2259-01)
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Zilog essentially ignored the Z800 in favor of their 32-bit
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The Z800 contrasts with Zilog's first 16-bit effort, the
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436:"Full Z80 Opcode List Including Undocumented Opcodes"
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369:"Zilog Z800 microprocessor chip quick description"
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206:More successful Z80 derivatives (from Zilog)
35:, and differed primarily in having on-chip
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490:
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322:"16-bits means more power for your money"
290:Learn how and when to remove this message
253:This article includes a list of general
111:
303:
7:
320:Geisler, Pamela A. (February 1982).
406:"R800 additional opcodes over Z80"
259:it lacks sufficient corresponding
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99:extended processing architecture
69:to incorporate emulation of the
73:in certain products in its own
16:Prototype 16-bit microprocessor
191:The Z800 was, in most ways, a
85:There was no expansion of the
1:
434:Harston, J.G. (1998-04-15).
419:Harston, J.G. (1997-09-09).
404:Harston, J.G. (2008-06-04).
310:EDN November 27, 1986, p133
27:microprocessor designed by
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367:Olsen, Dave (1985-01-08).
210:Apart from the successful
382:Skot, Jeff (1985-05-16).
103:extended processing units
384:"Z800 preliminary specs"
274:more precise citations.
732:16-bit microprocessors
214:(developed largely by
198:Hitachi developed the
187:Reason for the failure
67:National Semiconductor
41:memory management unit
727:Zilog microprocessors
356:San Jose, California
77:of microprocessors.
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594:Operating systems
362:. September 1983.
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81:Short description
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328:. pp. 26–27
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637:Hitachi HD64180
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559:Microcontroller
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326:Data Processing
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651:Sharp LH0080
641:Zilog Z64180
537:Z8000 series
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439:. Retrieved
424:. Retrieved
409:. Retrieved
387:. Retrieved
372:. Retrieved
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330:. Retrieved
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193:minicomputer
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124:address bus
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75:32000 series
60:
45:
20:
18:
661:Rabbit 2000
646:NEC µPD780C
624:compatibles
272:introducing
63:Zilog Z8000
721:Categories
632:ASCII R800
584:Encore! 32
572:Z8 Encore!
494:Z80 series
441:2009-07-16
426:2009-07-16
411:2009-07-16
389:2009-07-16
374:2009-07-16
345:References
255:references
212:Zilog Z180
71:Intel 8080
21:Zilog Z800
666:КР1858ВМ1
280:July 2009
118:# of pins
676:MMN80CPU
487:Products
121:data bus
87:register
615:Related
602:Z80-RIO
332:2 March
268:improve
216:Hitachi
200:HD64180
105:(EPU).
689:People
579:Z80182
549:Z80000
257:, but
227:24-bit
220:32-bit
177:16-bit
171:Z8216
157:Z8208
149:16-bit
143:Z8116
129:Z8108
115:part #
48:Z80000
39:and a
25:16-bit
23:was a
544:Z8000
480:Zilog
360:Zilog
236:Notes
163:8-bit
135:8-bit
37:cache
29:Zilog
671:U880
622:Z80
528:eZ80
523:Z380
516:Z800
511:Z280
506:Z180
334:2023
230:eZ80
223:Z380
101:and
56:CMOS
52:Z280
19:The
501:Z80
33:Z80
723::
639:,
567:Z8
358::
354:.
324:.
174:64
160:64
146:40
132:40
58:.
472:e
465:t
458:v
444:.
429:.
414:.
392:.
377:.
336:.
293:)
287:(
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278:(
264:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.