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'''MC6800''' 是摩托罗拉第一款微处理器[[摩托罗拉]]一款1974年投产的8位[[微处理器]]，它是M6800微计算机系统的一员，这个系统还包括了其他不同的[[集成电路]]、[[隨機存取記憶體|RAM]]、[[ROM]]和芯片。M6800系统发布于1974年3月，当年年底进入大规模生产。6800的架构和指令系统受到了日后流行的[[迪吉多]][[PDP-11]]小型计算机的影响。它有一个16位的地址总线和8位的双向数据总线，最大支持64KB的内存。在7种不同的寻址模式下，它的72条指令可提供192项作业码。原始版MC6800[[时钟频率]]可达1MHz，后续版本则提升到了2MHz。M6800系统成员的一个显著特征是只需要5伏特的电源，相比之下當時其他一些微处理器需使用3种不同的[[电压]]。。
== 開發历史 ==
摩托罗拉的微处理器计划开始于1971年，开发团队的主要成员为设计师汤姆·班尼特（Tom Bennett），工程主管杰夫·拉韦尔（Jeff LaVell），产品销售林克·杨以及系统设计师麦克·威尔斯（Mike Wiles）、吉因·施赖伯（Gene Schriber）和道格·鲍威尔（Doug Powell）<ref name = "Malone 1995">{{Cite book | last = Malone | first = Michael S. | title = The Microprocessor: A Biography | publisher = Springer-Verlag | date = 1995 | location = New York | pages = 141–147 | isbn = 0387943420}}</ref>。他们工作于[[亚利桑那州]]的梅瑟<ref>Motorola 6800 Oral History (2008)</ref>。汤姆·班尼特拥有工程控制方面的工作背景，他曾设计过使用[[金屬氧化物半導體場效電晶體|-{zh-cn:MOS管;zh-tw:MOSFET}-]]的IC作成电子计算器<ref name = "1964 MOS IC">{{Cite web | title = 1964 - First Commercial MOS IC Introduced | publisher = Computer History Museum | date = 2007 | url = http://www.computerhistory.org/semiconductor/timeline/1964-Commecial.html | accessdate = August 9, 2010}} </ref>，1971年他加入摩托罗拉开始了6800的设计工作<ref name ="Bennett 3962682"> Bennett, Thomas H., "Split low order internal address bus for microprocessor", [http://www.google.com/patents/about?id=6w4wAAAAEBAJ US Patent 3962682], issued June 8, 1976. Bennett is listed as an inventor on 18 M6800 family patents.</ref>。
杰夫·拉韦尔在1966年加入摩托罗拉，拥有计算机行业的经验。1971年他领导了一个团队去调查[[惠普]]、[[NCR]]、[[DEC]]等大客户的需求，希望能用低成本的[[超大规模集成电路]]来满足这些要求。调查的结果是诞生了一个由15个模块组成的系列产品，每个模块都被集成在一个集成电路之内<ref>Motorola 6800 Oral History (2008)</ref>。M6800内就集成了部分这种模块，后来杰夫又使用传统方法设计电路进行比较。为了达到同样的性能，他用了安装在5块25厘米见方电路版上的451个小型[[TTL]]芯片。后来通过使用ROM和MSI的逻辑器件进行了精简，即便这样还是要用114个集成电路<ref>''Electronics'' April 18, 1974. Photo of boards on page 82, description of circuit on page 93.</ref>。
第一块量产型MC6800生产于1974年2月，工程样品被交给了制定客户的手中。同年6月，惠普已经开发出了基于6800的桌面级计算器原型机<ref>Motorola 6800 Oral History (2008) pp. 9, 15</ref><ref name = "MD Oct 1975 HP 9815">{{Cite journal | title = HP designs custom 16-bit uC chip | journal = Microcomputer Digest | volume = 2 | issue = 4 | page = p. 8 | publisher = Microcomputer Associates | location = Cupertino CA | date = October 1975 | url = http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n04_Oct75.pdf}}</ref>。由于使用了新式单一电压供电的N沟道MOS管，加工起来颇为困难。M6800微机系统最终于1974年11月投产，摩托罗拉采用了和[[Intel 8080|英特尔8080]]相同的售价，也就是360美元<ref name = "MC6850 1975">{{Cite journal | title = Motorola microprocessor set is 1 MHz n-MOS | journal = Control Engineering | volume = 21 | issue = 11 | page = p. 11 | date = November 1974}} </ref><ref name = "Intel $360">{{cite book | last = Intel Corporation | coauthors = Glynnis Thompson Kaye (Editor) | title = A Revolution in Progress - A History to Date of Intel | publisher = Intel Corporation | date = 1984 | page = 14 | url = http://www.intel.com/museum/archives/brochures/brochures.htm | id = Order number:231295}} </ref>。除了发布完整的外围芯片之外，摩托罗拉还提供了软硬件开发系统。用户可在分时复用的电脑上使用软件开发工具或是利用内部电脑系统。软件系统是用典型的[[汇编语言]]写成的，可以运行在微处理器上。开发系统包括文档编辑器、汇编程序和[[模拟器]]<ref name = "6800 programming manual">{{Cite book | title = M6800 Microprocessor Programming Manual | publisher = Motorola Semiconductor Products | date = 1975 | location = Phoenix AZ}}</ref>。核心设计工作在1974年中期就已经完成了，许多工程师在这之后离开了开发团队或摩托罗拉。这是由于[[得克萨斯]]新工厂带来的搬迁问题<ref name = " Hoefler July 1976">{{Cite journal | last = Hoefler | first = Don | title = Backfire | journal = Microelectronics News | page = p. 3 | location = Santa Clara, CA | date = July 3, 1976 | url = http://smithsonianchips.si.edu/schreiner/1976/h76713.htm}}</ref>、裁员危机<ref name = "Electronics Nov 13 1975">{{Cite journal | last = Waller | first = Larry | title = Motorola seeks to end skid | journal = Electronics | volume = 48 | issue = 23 | pages = pp. 96–98 | publisher = McGraw-Hill | location = New York | date = November 13, 1975}}</ref>以及摩托罗拉对于开发低成本处理器的消极态度<ref>Motorola 6800 Oral History (2008) p. 18</ref> 。最终，楚克·佩德尔（Chuck Peddle）等人离开摩托罗拉加入了[[MOS科技公司]]，在那里他们开发了售价20美元的[[MOS 6502]]处理器<ref name = "6502 Computer Sep 1975">{{Cite journal | title = MOS 6502 the second of a low cost high performance microprocessor family | journal = Computer | volume = 8 | issue = 9 | pages = pp 38–39 | publisher = IEEE Computer Society | date = September 1975 | url = http://commons.wikimedia.org/wiki/File:MOS_6501_6502_Ad_Sept_1975.jpg | doi = 10.1109/C-M.1975.219074 }}</ref>。
==设计==
6800以PDP-11的处理器为结构模板 ，两者都能兼容TTL，拥有8位双向数据线，16位[[堆栈]][[指针_(信息学)|指针]]，16位[[地址总线]]可以支持64KB的[[内存]]，整个微处理器以40针的[[DIP包裝|DIP]]结构进行封装。6800拥有4000个[[晶体管]]，2个数据缓存和一个16位的指针缓存。在直接地址模式下可以快速读取内存中的前256个字节。输入输出系统的地址格式同内存一样，所以没有特殊的输入、输出指令。6800在最高地址上载入程序指针然后在内存中储存它<ref name = "μP Roundup 1976">{{Cite journal | title = Microprocessors: Designers gain new freedom as options multiply | journal = Electronics | volume = 49 | issue = 8 | pages = pp. 78–100 | publisher = McGraw-Hill | location = New York | date = April 15, 1976}} </ref>。
6800使用3态控制器阻止地址总线允许另一个设备使用直接记忆通道。在处理器未加载时[[磁盘]]控制器就能将数据存入内存，两块6800可以使用同一个内存<ref>Motorola 6800 Oral History (2008) pp. 15-16</ref>。
同8080相比，6800处理指令需要的指令周期更少，2MHz的8080处理能力尚且不如1MHz的6800。6800的最低工作频率可以降到100KHz<ref name = "MD Sep 1975 8080A">{{Cite journal | title = Intel's Higher Speed 8080 μP | journal = Microcomputer Digest | volume = 2 | issue = 3 | page = p. 7 | publisher = Microcomputer Associates | location = Cupertino CA | date = September 1975 | url = http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n03_Sep75.pdf}}</ref>。
{{noteTA
|G1=IT
}}
最初，设计人员计划将6800的核心控制在边长4.6毫米之内，但最终这一数字上升到了5.4毫米，核心面积为29.0 mm<sup>2</sup>。对于70年代主流的3英寸[[晶圆]]来说，可以切割出190个4.6毫米边长的芯片，或是140个5.4毫米的芯片<ref name = "Chip Yield">{{Cite journal | last = Wikes | first = W. E. | title = A Microprocessor Chip Designed with the User in Mind | journal = Computer | volume = 10 | issue = 1 | pages = pp. 18–22 | publisher = IEEE | date = January 1977 | doi = 10.1109/C-M.1977.217492}} This paper describes the Electronic Arrays EA9002 microprocessor that was 200 by 200 mils and fabricated on a 3 inch silicon wafer.</ref><ref name = "Elmasry 1981">{{Cite book | editor-last = Elmasry | editor-first = Mohamed I. | title = Digital MOS integrated circuits | publisher = IEEE Press | date = 1981 | isbn = 9780879421526 }}</ref>。不过，1975年在MC6800上使用耗尽模式后，它的核心长度降到了4毫米。更小的核心也带来了频率的提升。后续型号MC68A00工作在1.5兆赫兹，MC68B00则工作在2MHz<ref name = "MC6800D March 1976">{{Cite journal | title = Electronics Newsletter: 6800 gains speed, lower prices by summer | journal = Electronics | volume = 49 | issue = 5 | page = p. 25 | publisher = McGraw-Hill | location = New York | date = March 4, 1976}}</ref><ref name = "Daniels 1996">{{Cite journal | last = Daniels | first = R. Gary | title = A Participant’s Perspective | journal = IEEE Micro | volume = 16 | issue = 5 | pages = pp. 21–31 | publisher = IEEE Computer Society | date = December 1996 | doi = 10.1109/40.546562}}</ref>。
==生產==
除了摩托罗拉自己以外，许多其他公司也生产了MC6800，如[[仙童半导体]]的F68A00S，汤姆逊的EF6800CM、EF6800P以及
AMI的S6800，S6800的最高频率甚至可达2.5兆赫兹<ref>[http://www.cpu-world.com/CPUs/6800/index.html Motorola 6800 microprocessor family]</ref>。
== 參考文獻 ==
{{reflist}}
== 開發历史 ==
摩托罗拉的微处理器计划开始于1971年，开发团队的主要成员为设计师汤姆·班尼特（Tom Bennett），工程主管杰夫·拉韦尔（Jeff LaVell），产品销售林克·杨以及系统设计师麦克·威尔斯（Mike Wiles）、吉因·施赖伯（Gene Schriber）和道格·鲍威尔（Doug Powell）<ref name = "Malone 1995">{{Cite book | last = Malone | first = Michael S. | title = The Microprocessor: A Biography | publisher = Springer-Verlag | date = 1995 | location = New York | pages = 141–147 | isbn = 0387943420}}</ref>。他们工作于[[亚利桑那州]]的梅瑟<ref>Motorola 6800 Oral History (2008)</ref>。汤姆·班尼特拥有工程控制方面的工作背景，他曾设计过使用[[金屬氧化物半導體場效電晶體|-{zh-cn:MOS管;zh-tw:MOSFET}-]]的IC作成电子计算器<ref name = "1964 MOS IC">{{Cite web | title = 1964 - First Commercial MOS IC Introduced | publisher = Computer History Museum | date = 2007 | url = http://www.computerhistory.org/semiconductor/timeline/1964-Commecial.html | accessdate = August 9, 2010}} </ref>，1971年他加入摩托罗拉开始了6800的设计工作<ref name ="Bennett 3962682"> Bennett, Thomas H., "Split low order internal address bus for microprocessor", [http://www.google.com/patents/about?id=6w4wAAAAEBAJ US Patent 3962682], issued June 8, 1976. Bennett is listed as an inventor on 18 M6800 family patents.</ref>。
杰夫·拉韦尔在1966年加入摩托罗拉，拥有计算机行业的经验。1971年他领导了一个团队去调查[[惠普]]、[[NCR]]、[[DEC]]等大客户的需求，希望能用低成本的[[超大规模集成电路]]来满足这些要求。调查的结果是诞生了一个由15个模块组成的系列产品，每个模块都被集成在一个集成电路之内<ref>Motorola 6800 Oral History (2008)</ref>。M6800内就集成了部分这种模块，后来杰夫又使用传统方法设计电路进行比较。为了达到同样的性能，他用了安装在5块25厘米见方电路版上的451个小型[[TTL]]芯片。后来通过使用ROM和MSI的逻辑器件进行了精简，即便这样还是要用114个集成电路<ref>''Electronics'' April 18, 1974. Photo of boards on page 82, description of circuit on page 93.</ref>。
第一块量产型MC6800生产于1974年2月，工程样品被交给了制定客户的手中。同年6月，惠普已经开发出了基于6800的桌面级计算器原型机<ref>Motorola 6800 Oral History (2008) pp. 9, 15</ref><ref name = "MD Oct 1975 HP 9815">{{Cite journal | title = HP designs custom 16-bit uC chip | journal = Microcomputer Digest | volume = 2 | issue = 4 | page = p. 8 | publisher = Microcomputer Associates | location = Cupertino CA | date = October 1975 | url = http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n04_Oct75.pdf}}</ref>。由于使用了新式单一电压供电的N沟道MOS管，加工起来颇为困难。M6800微机系统最终于1974年11月投产，摩托罗拉采用了和[[Intel 8080|英特尔8080]]相同的售价，也就是360美元<ref name = "MC6850 1975">{{Cite journal | title = Motorola microprocessor set is 1 MHz n-MOS | journal = Control Engineering | volume = 21 | issue = 11 | page = p. 11 | date = November 1974}} </ref><ref name = "Intel $360">{{cite book | last = Intel Corporation | coauthors = Glynnis Thompson Kaye (Editor) | title = A Revolution in Progress - A History to Date of Intel | publisher = Intel Corporation | date = 1984 | page = 14 | url = http://www.intel.com/museum/archives/brochures/brochures.htm | id = Order number:231295}} </ref>。除了发布完整的外围芯片之外，摩托罗拉还提供了软硬件开发系统。用户可在分时复用的电脑上使用软件开发工具或是利用内部电脑系统。软件系统是用典型的[[汇编语言]]写成的，可以运行在微处理器上。开发系统包括文档编辑器、汇编程序和[[模拟器]]<ref name = "6800 programming manual">{{Cite book | title = M6800 Microprocessor Programming Manual | publisher = Motorola Semiconductor Products | date = 1975 | location = Phoenix AZ}}</ref>。核心设计工作在1974年中期就已经完成了，许多工程师在这之后离开了开发团队或摩托罗拉。这是由于[[得克萨斯]]新工厂带来的搬迁问题<ref name = " Hoefler July 1976">{{Cite journal | last = Hoefler | first = Don | title = Backfire | journal = Microelectronics News | page = p. 3 | location = Santa Clara, CA | date = July 3, 1976 | url = http://smithsonianchips.si.edu/schreiner/1976/h76713.htm}}</ref>、裁员危机<ref name = "Electronics Nov 13 1975">{{Cite journal | last = Waller | first = Larry | title = Motorola seeks to end skid | journal = Electronics | volume = 48 | issue = 23 | pages = pp. 96–98 | publisher = McGraw-Hill | location = New York | date = November 13, 1975}}</ref>以及摩托罗拉对于开发低成本处理器的消极态度<ref>Motorola 6800 Oral History (2008) p. 18</ref> 。最终，楚克·佩德尔（Chuck Peddle）等人离开摩托罗拉加入了[[MOS科技公司]]，在那里他们开发了售价20美元的[[MOS 6502]]处理器<ref name = "6502 Computer Sep 1975">{{Cite journal | title = MOS 6502 the second of a low cost high performance microprocessor family | journal = Computer | volume = 8 | issue = 9 | pages = pp 38–39 | publisher = IEEE Computer Society | date = September 1975 | url = http://commons.wikimedia.org/wiki/File:MOS_6501_6502_Ad_Sept_1975.jpg | doi = 10.1109/C-M.1975.219074 }}</ref>。
==设计==
6800以PDP-11的处理器为结构模板 ，两者都能兼容TTL，拥有8位双向数据线，16位[[堆栈]][[指针_(信息学)|指针]]，16位[[地址总线]]可以支持64KB的[[内存]]，整个微处理器以40针的[[DIP包裝|DIP]]结构进行封装。6800拥有4000个[[晶体管]]，2个数据缓存和一个16位的指针缓存。在直接地址模式下可以快速读取内存中的前256个字节。输入输出系统的地址格式同内存一样，所以没有特殊的输入、输出指令。6800在最高地址上载入程序指针然后在内存中储存它<ref name = "μP Roundup 1976">{{Cite journal | title = Microprocessors: Designers gain new freedom as options multiply | journal = Electronics | volume = 49 | issue = 8 | pages = pp. 78–100 | publisher = McGraw-Hill | location = New York | date = April 15, 1976}} </ref>。
6800使用3态控制器阻止地址总线允许另一个设备使用直接记忆通道。在处理器未加载时[[磁盘]]控制器就能将数据存入内存，两块6800可以使用同一个内存<ref>Motorola 6800 Oral History (2008) pp. 15-16</ref>。
同8080相比，6800处理指令需要的指令周期更少，2MHz的8080处理能力尚且不如1MHz的6800。6800的最低工作频率可以降到100KHz<ref name = "MD Sep 1975 8080A">{{Cite journal | title = Intel's Higher Speed 8080 μP | journal = Microcomputer Digest | volume = 2 | issue = 3 | page = p. 7 | publisher = Microcomputer Associates | location = Cupertino CA | date = September 1975 | url = http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n03_Sep75.pdf}}</ref>。
{{noteTA
|G1=IT
}}
最初，设计人员计划将6800的核心控制在边长4.6毫米之内，但最终这一数字上升到了5.4毫米，核心面积为29.0 mm<sup>2</sup>。对于70年代主流的3英寸[[晶圆]]来说，可以切割出190个4.6毫米边长的芯片，或是140个5.4毫米的芯片<ref name = "Chip Yield">{{Cite journal | last = Wikes | first = W. E. | title = A Microprocessor Chip Designed with the User in Mind | journal = Computer | volume = 10 | issue = 1 | pages = pp. 18–22 | publisher = IEEE | date = January 1977 | doi = 10.1109/C-M.1977.217492}} This paper describes the Electronic Arrays EA9002 microprocessor that was 200 by 200 mils and fabricated on a 3 inch silicon wafer.</ref><ref name = "Elmasry 1981">{{Cite book | editor-last = Elmasry | editor-first = Mohamed I. | title = Digital MOS integrated circuits | publisher = IEEE Press | date = 1981 | isbn = 9780879421526 }}</ref>。不过，1975年在MC6800上使用耗尽模式后，它的核心长度降到了4毫米。更小的核心也带来了频率的提升。后续型号MC68A00工作在1.5兆赫兹，MC68B00则工作在2MHz<ref name = "MC6800D March 1976">{{Cite journal | title = Electronics Newsletter: 6800 gains speed, lower prices by summer | journal = Electronics | volume = 49 | issue = 5 | page = p. 25 | publisher = McGraw-Hill | location = New York | date = March 4, 1976}}</ref><ref name = "Daniels 1996">{{Cite journal | last = Daniels | first = R. Gary | title = A Participant’s Perspective | journal = IEEE Micro | volume = 16 | issue = 5 | pages = pp. 21–31 | publisher = IEEE Computer Society | date = December 1996 | doi = 10.1109/40.546562}}</ref>。
==生產==
除了摩托罗拉自己以外，许多其他公司也生产了MC6800，如[[仙童半导体]]的F68A00S，汤姆逊的EF6800CM、EF6800P以及
AMI的S6800，S6800的最高频率甚至可达2.5兆赫兹<ref>[http://www.cpu-world.com/CPUs/6800/index.html Motorola 6800 microprocessor family]</ref>。
== 參考文獻 ==
{{reflist}}