page_title: Motorola 6800
section_title: Development team
hierarchical_section_title: Motorola 6800 / History / Development team
caption_attribution_description: English: Motorola provided a comprehensive set of documentation for the M6800 Microcomputer System. (MC6800 referred to the microprocessor chip, M6800 referred to the whole system including peripheral chips.) From top to bottom MIKBUG Engineering Note 100 (1975) M6800 Microcomputer System Design Data (1976) M6800 System Reference and Data Sheets (1975) M6800 Programming Reference Manual (1976) M6800 Microprocessor Applications Manual (1975) The Microprocessor Applications Manual had 714 pages and describes how to build a point-of-sale terminal that has a bar code reader, a printer, a keyboard, a display and a floppy disk. Hardware schematics and software code is provided.
context_page_description: The 6800 is an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips. A significant design feature was that the M6800 family of ICs required only a single five-volt power supply at a time when most other microprocessors required three voltages. The M6800 Microcomputer System was announced in March 1974 and was in full production by the end of that year.
  The 6800 has a 16-bit address bus that can directly access 64 KB of memory and an 8-bit bi-directional data bus. It has 72 instructions with seven addressing modes for a total of 197 opcodes. The original MC6800 could have a clock frequency of up to 1 MHz. Later versions had a maximum clock frequency of 2 MHz.
  In addition to the ICs, Motorola also provided a complete assembly language development system. The customer could use the software on a remote timeshare computer or on an in-house minicomputer system. The Motorola EXORciser was a desktop computer built with the M6800 ICs that could be used for prototyping and debugging new designs.
context_section_description: Motorola did not chronicle the development of the 6800 microprocessor the way that Intel did for their microprocessors. In 2008 the Computer History Museum interviewed four members of the 6800 microprocessor design team. Their recollections can be confirmed and expanded by magazine and journal articles written at the time.
  The Motorola microprocessor project began in 1971 with a team composed of designer Tom Bennett, engineering director Jeff LaVell, product marketer Link Young and systems designers Mike Wiles, Gene Schriber and Doug Powell. They were all located in Mesa, Arizona. By the time the project was finished, Bennett had 17 chip designers and layout people working on five chips. LaVell had 15 to 20 system engineers and there was another applications engineering group of similar size.
  Tom Bennett had a background in industrial controls and had worked for Victor Comptometer in the 1960s designing the first electronic calculator to use MOS ICs, the Victor 3900. In May 1969 Ted Hoff showed Bennett early diagrams of the Intel 4004 to see if it would meet their calculator needs. Bennett joined Motorola in 1971 to design calculator ICs. He was soon assigned as the chief architect of the microprocessor project that produced the 6800. Others have taken credit for designing the 6800. In September 1975 Robert H. Cushman, EDN magazine's microprocessor editor, interviewed Chuck Peddle about MOS Technology's new 6502 microprocessor. Cushman then asked "Tom Bennett, master architect of the 6800", to comment about this new competitor. After the 6800 project Bennett worked on automotive applications and Motorola became a major supplier of microprocessors used in automobiles.
  Jeff LaVell joined Motorola in 1966 and worked in the computer industry marketing organization. LaVell had previously worked for Collins Radio on their C8500 computer that was built with small scale ECL ICs. In 1971, he led a group that examined the needs of their existing customers such as Hewlett-Packard, National Cash Register, Control Data Corporation (CDC), and Digital Equipment Corporation (DEC). They would study the customer's products and try to identify functions that could be implemented in larger integrated circuits at a lower cost. The result of the survey was a family of 15 building blocks; each could be implemented in an integrated circuit. Some of these blocks were implemented in the initial M6800 release and more were added over the next few years. To evaluate the 6800 architecture while the chip was being designed, LaVell's team built an equivalent circuit using 451 small scale TTL ICs on five 10 by 10 inch (25 by 25 cm) circuit boards. Later they reduced this to 114 ICs on one board by using ROMs and MSI (medium scale integration) logic devices.
  John Buchanan was a memory designer at Motorola when Bennett asked him to design a voltage doubler for the 6800. Typical n-channel MOS IC's required three power supplies: -5 volts, +5 volts and +12 volts. The M6800 family was to use only one, +5 volts. It was easy to eliminate the -5 volt supply but the MOS transistors needed a supply of 10 to 12 volts. This on-chip voltage doubler would supply the higher voltage and Buchanan did the circuit design, analysis and layout for the 6800 microprocessor. He received patents on the voltage doubler and the 6800 chip layout. Rod Orgill assisted Buchanan with analyses and 6800 chip layout. Later Orgill would design the MOS Technology 6501 microprocessor that was socket compatible with the 6800.
  Bill Lattin joined Motorola in 1969 and his group provided the computer simulation tools for characterizing the new MOS circuits in the 6800. Lattin and Frank Jenkins had both attended UC Berkeley and studied computer circuit simulators under Donald Pederson, the designer of the SPICE circuit simulator. Motorola's simulator, MTIME, was an advanced version of the TIME circuit simulator that Jenkins had developed at Berkeley. The group published a technical paper, "MOS-device modeling for computer implementation" in 1973 describing a "5-V single-supply n-channel technolog
caption: MIKBUG was part of the extensive M6800 microcomputer support developed by Motorola's Application Engineering Group.
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