MOS Technology, Inc., also known as Commodore Semiconductor Group, was a microprocessor and calculator company famous for its 6502 processor. Image File history File links MOSlogo_full. ... A microprocessor (sometimes abbreviated µP) is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC). ... For other uses, see Calculator (disambiguation). ... The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ...

(Note that, despite the name similarity, MOS Technology is not the same company as Mostek.) Mostek was founded in 1969 by ex-employees of Texas Instruments. ...

History

MOS originally started up to provide a second source for Texas Instruments designed electronic calculators and the chips inside them. They also produced Atari's custom PONG chip for a short time. As the calculator market grew MOS eventually became largely beholden to Commodore Business Machines, who bought practically all of their supply for their line of calculators.^[1] Texas Instruments (NYSE: TXN), better known in the electronics industry (and popularly) as TI, is an American company based in Dallas, Texas, USA, renowned for developing and commercializing semiconductor and computer technology. ... This article or section does not cite its references or sources. ... Pong helped bring computerized video games into everyday life. ... Commodore is the commonly used name for Commodore International, was an American electronics company based in West Chester, Pennsylvania which was a vital player in the home/personal computer field in the 1980s. ...

Things changed dramatically in 1975. Several of the designers of the Motorola 6800 left the company shortly after its release, apparently in disgust. At the time there was no such thing as a "design-only" firm (known as a fabless semiconductor company today), so they had to join a chip-building company to produce any of their designs. MOS was a small firm with good credentials in the right area, the East coast of the USA. Motorola (NYSE: MOT) is an American international communications company based in Schaumburg, Illinois, a Chicago suburb. ... Motorola 6800 Microprocessor The 6800 is a microprocessor produced by Motorola and released shortly after the Intel 8080 in 1975. ... A fabless semiconductor company specializes in the design and sale of hardware devices implemented on semiconductor chips. ...

The team of four design engineers was headed by Chuck Peddle and included Bill Mensch. At MOS they set about building a new CPU that would outperform the 6800 while being similar to it in purpose. The resulting 6501 design was somewhat similar to the 6800, but by using several simplifications in the design, the 6501 would be up to four times faster. Electronics engineer Chuck Peddle is mostly known as the main designer of the MOS Technology 6502 microprocessor; the KIM-1 SBC; and its successor the Commodore PET school/business/home computer, both based on the 6502. ... William D. Mensch is the inventor of the 65C02, and W65816 derivatives of the famous MOS Technology 6502 microprocessor, and head of the Western Design Center. ... CPU redirects here. ... The 6501 is an eight-bit microprocessor, the first sold by MOS Technology. ...

Mask fixing

In addition, MOS had a secret weapon, the ability to "fix" its masks.^[2] Masks are the large drawings of the chip that are photo-reduced to make the pattern from which chips are made – a process similar to photocopying. All masks end up with flaws, both as a result of design problems in the chip itself, as well as side effects from the photo-reduction process. When a chip is made with this mask there is a chance that some of these flaws will end up "expressed" on the chip. If too many of them are expressed, that particular chip will not work. A small, much-used Xerox copier in a high school library. ...

If a chip design with five design flaws results in a mask with ten flaws in total, there is no point in making another mask because it will have the same five design flaws plus some other set of five copying flaws. So companies simply built chips with these masks, and threw away broken chips. In the late 1970s this meant throwing away 70% or more of the completed chips. The price of a chip is largely defined by the yield, the measure of how many work, so improving this number can lower the price and raise the gross profit dramatically. Gross profit or sales profit or gross operating profit is the difference between revenue and the cost of making a product or providing a service, before deducting overheads, payroll, taxation, and interest payments. ...

MOS's engineers had learned the trick of fixing their masks after they were made. This allowed them to correct the major flaws in a series of small fixes, eventually producing a mask with a very low flaw rate. The company's production lines typically reversed the numbers others were achieving; even the early runs of a new CPU design –what would become the 6502– were achieving a success rate of 70% or better. This meant that not only were its designs faster, they cost much less as well.

6502 family

When the 6501 was announced, Motorola launched a lawsuit almost immediately. Although the 6501 was not compatible with the 6800, it could nevertheless be plugged into existing motherboard designs because it used the same arrangement of pins. That was enough, apparently, to allow Motorola to sue. Sales of the 6501 basically stopped, and the lawsuit would drag on for many years before MOS was eventually forced to pay a paltry $200,000 in fines. A motherboard, also known as a mainboard, system board, or logic boards on Apple Computers, and sometimes abbreviated as mobo (generally credited to the magazine Maximum PC) is the central or primary circuit board making up a complex electronic system, such as a modern computer. ...

In the meantime the 6502 had gone on sale at 1 MHz in September 1975 for a mere $25. It was essentially identical to the 6501, differing only in pin layout. Due to its speed it outran the more complex and expensive 6800, and Intel 8080, but cost much less and was easier to work with. Although it did not have the advantage of being able to be used in existing Motorola hardware like the 6501, it was so inexpensive that it quickly overran the 6800 in popularity anyway, making that a moot point. The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ... Intel C8080A processor. ...

Image of the innards of a Commodore 64 showing some important MOS Technology circuits: the 6510 CPU (long chip, lower left) and the 6581 SID (right). The production week/year (WWYY) of each chip is given below its name.

The 6502 was so cheap, that many people believed it was a scam when MOS first showed it at a 1975 trade show. They were not aware of MOS's masking techniques and when they calculated the price per chip at normal yield rates it did not add up. But any hesitation to buy it evaporated when both Motorola and Intel dropped the prices on their own designs from $179 to $69 at the same show in order to compete. Their moves legitimized the 6502. By show's end the wooden barrel full of samples was empty. Large version of the illustration used at the MOS Technology page. ... Large version of the illustration used at the MOS Technology page. ... The Commodore 64 is the best selling single personal computer model of all time. ... Image of the innards of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). ... MOS Technology SIDs: The right image shows a 6581 from MOS Technology, at the time they were known as the Commodore Semiconductor Group (CSG) and the left image shows an 8580 from MOS Technology. ...

The 6502 would quickly go on to be one of the most popular chips of its day. A number of companies licensed the 650x line from MOS, including Rockwell International, GTE, Synertek, and Western Design Center (WDC). Rockwell can refer to: Rockwell International - a defense company in the United States Rockwell Automation - an industrial automation company that descended from Rockwell International Rockwell Collins - a communications and aviation electronics company that also descended from Rockwell International Willard Rockwell - businessman who helped shape and name what became Rockwell International... Categories: Corporation stubs | Communications companies of the United States | Defunct companies | Telephone companies | Public Utilities ... Synertek was founded in 1973 as a masked ROM house that branched out into a fairly broad offering of MOS/LSI circuits (Static RAMs, ROMs, EPROMS, Dynamic and Static Shift Registers) and then sometime before 1979 became a second source to MOS Technologys 6502 microprocessor. ... If you were looking for the Western Digital Corporation, see Western Digital. ...

A number of different versions of the basic CPU, known as the 6503 through 6507, were offered in 28-pin packages for lower cost. The various models removed signal or address pins. Far and away the most popular of these was the 6507, which was used in the Atari 2600 and in Atari disk drives. The 6504 was sometimes used in printers. MOS also released a series of similar CPUs using external clocks, which added a "1" to the name in the 3rd digit, as the 6512 through 6515. These were useful in systems where the clock support was already being provided on the motherboard by some other chip. The final addition was the "crossover" 6510, used in the Commodore 64, with additional I/O ports. The 6507 is an 8-bit microprocessor from MOS Technology, Inc. ... The Atari 2600, released in October 1977, was the first successful video game console to use plug-in cartridges instead of having one or more games built in. ... Image of the innards of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). ... The Commodore 64 is the best selling single personal computer model of all time. ...

Commodore Semiconductor Group

However successful the 6502 was, the company itself was having problems. At about the time the CPU was released the entire calculator market collapsed, and MOS's only existing products stopped shipping. Soon they were in serious financial trouble. Rescue came in the form of Commodore, who bought the entire company in a stock trade, on the condition that Chuck Peddle would join Commodore as chief engineer. The deal went through, and while the firm basically became Commodore's production arm, they continued using the name MOS for some time so that manuals would not have to be reprinted. After a while MOS became the Commodore Semiconductor Group (CSG). Despite being renamed to CSG, all chips produced were still stamped with the old "MOS" logo until 1989.

MOS had previously designed a simple computer kit called the KIM-1, primarily to "show off" the 6502 chip. At Commodore, Peddle convinced the owner, Jack Tramiel, that calculators were a dead end, and that home computers would soon be huge. A repackaged KIM with a new display driver and keyboard became the Commodore PET computer. The KIM-1, short for Keyboard Input Monitor, was a small 6502-based microcomputer kit developed and produced by MOS Technology, Inc. ... Jack Tramiel (born 1928) is a businessman, famous for founding Commodore International, manufacturer of the Commodore 64 and Commodore Amiga home computers. ... The PET (Personal Electronic Transactor) was a home-/personal computer produced by Commodore starting in the late 1970s. ...

However, the original design group appeared to be even less interested in working for Jack Tramiel than it had for Motorola, and the team quickly started breaking up. One result was that the newly-completed 6522 (VIA) chip was left undocumented for years.

Bill Mensch left MOS even before the Commodore takeover, and moved home to Mesa, AZ from MOS's Norristown, PA. After a short stint consulting for a local company called ICE, he set up the Western Design Center (WDC) in 1978. As a licensee of the 6502 line, their first products were bug-fixed, power-efficient CMOS versions of the 6502 (the 65C02, both as a separate chip and embedded inside a microcontroller called the 65C150). But then they expanded the line greatly with the introduction of the 65816, a fairly straightforward 16-bit upgrade of the original 65C02 that could also run in 8-bit mode for compatibility. The design of the similar-in-concept 32-bit 65832 CPU was completed, but not put into production. Since then WDC have moved much of the original MOS catalog to CMOS, and the 6502 continues to be a popular CPU in embedded systems, like medical equipment and car dashboard controllers. Mesa is a city in Maricopa County, Arizona and part of the Phoenix-Mesa-Scottsdale Metropolitan Area. ... Norristown is a home rule municipality in Montgomery County, Pennsylvania, 17 miles (27 km) west by north of Philadelphia, on the Schuylkill River. ... If you were looking for the Western Digital Corporation, see Western Digital. ... Static CMOS Inverter Complementary-symmetry/metal-oxide semiconductor (CMOS) (see-moss, IPA:), is a major class of integrated circuits. ... The 65C02 Microprocessor is a slightly upgraded version of the popular and venerable MOS_Technology 6502 microprocessor. ... The integrated circuit from an Intel 8742, an 8-bit microcontroller that includes a CPU running at 12 MHz, 128 bytes of RAM, 2048 bytes of EPROM, and I/O in the same chip. ... The 65816 Microprocessor (also: 65C816), a 16_bit CPU developed by the Western Design Center (WDC), is an expanded and compatible successor to the venerable MOS Technology 6502. ... In computer science, 16-bit is an adjective used to describe integers that are at most two bytes wide, or to describe CPU architectures based on registers, address buses, or data buses of that size. ... 8-bit refers to the number of bits used in the data bus of a computer. ... 32-bit is a term applied to processors, and computer architectures which manipulate the address and data in 32-bit chunks. ... A router, an example of an embedded system. ...

GMT Microelectronics

After Commodore's bankruptcy in 1994, Commodore Semiconductor Group, MOS's successor, was bought by its former management for about $4.3 million, plus an additional $1 million to cover miscellaneous expenses including EPA liens. Dennis Peasenell became CEO. In December 1994, EPA entered into a Prospective Purchase Agreement (limited the company's liability in exchange for sharing the costs of cleanup) with GMT Microelectronics. In 1995, the company, operating under the name GMT Microelectronics (Great Mixed-signal Technologies), reopened MOS Technologies' original, circa-1970 one-micrometre fab in Norristown, Pennsylvania that Commodore had closed in 1992. GMT would have provided foundry services based on TelCom's Bipolar and SiCr Thin Film Resistor processes and would have been licensed alternate sources for TelCom's Bipolar based products. With production running at 10000 wafers (size 5) per month, produciong CMOS BiCMOS NMOS BIPOLAR SOI. The plant had been on the EPA's National Priorities List of hazardous waste sites since 1989. By 1999 it had $21 million in revenues and 183 employees, within 3 years. However, in 2001 the EPA shut the plant down. GMT ceased operations and was liquidated. EPA redirects here. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the size of a droplet of mist or fog. ... It has been suggested that this article or section be merged into Fabrication plant. ... This article is about the year 2001. ...

Products

• KIM-1 – single board computer (kit)/CPU evaluation board, based on 6502
• MOS Technology 4510 – CPU (CSG 65CE02) with two CIAs on-chip; 3.45 MHz
• MOS Technology 6501 – CPU pin-compatible with Motorola 6800
• MOS Technology 6502 – CPU equal to 6501 except 6800 pin-compatibility
• MOS Technology 6507 – CPU with 13 address pins
• MOS Technology 6508 – CPU with 256 B RAM and 8 I/O pins
• MOS Technology 6509 – CPU with 20 address pins
• MOS Technology 6510 – CPU with clock pins and I/O ports,
• MOS Technology 6520 – PIA Peripheral Interface Adapter
• MOS Technology 6522 – VIA Versatile Interface Adapter
• MOS Technology TPI   – TPI Tri-Port Interface, aka 6523/6525
• MOS Technology CIA   – CIA Complex Interface Adapter, aka 6526/8520/8521
• MOS Technology SPI – SPIA Single Port Interface Adapter
• MOS Technology RRIOT – RRIOT ROM-RAM-I/O Timer
• MOS Technology 6532 – RIOT RAM-I/O Timer
• MOS Technology 6545 – CRTC CRT Controller
• MOS Technology 6551 – ACIA Asynchronous Communications Interface Adapter
• MOS Technology VIC   – VIC Video Interface Chip, aka 6560 (NTSC) and 6561 (PAL)
• MOS Technology VIC-II aka 6567/8562/8564 (NTSC) and 6569/8565/8566 (PAL)
• MOS Technology SID   – SID Sound Interface Device, aka 6581/6582/8580
• MOS Technology TED  – TED Text Editing Device, aka 7360/8360 (HMOS-I/II)
• MOS Technology 8500 – CPU HMOS-II Version of 6510
• MOS Technology 8501 – CPU HMOS-II 6502 with 7-bit I/O port
• MOS Technology 8502 – CPU compatible with 6510 but able to run at 2 MHz
• MOS Technology 8551 – ACIA Asynchronous Communications Interface Adapter, HMOS-II variant of the 6551
• MOS Technology VDC – VDC Video Display Controller
• MOS Technology 8568 – VDC with composite HSYNC, VSYNC, and RDY interrupt
• MOS Technology 8722 – MMU Memory Management Unit
• MOS Technology 8726 – REC RAM Expansion Controller
• MOS Technology AGNUS – Address Generator Unites
• MOS Technology 8362 – DENISE Display Encoder
• MOS Technology 8373 – ECS DENISE Display Encoder
• MOS Technology 8364 – PAULA Port Audio UART and Logic
• MOS Technology 5719 – GARY Gate Array

The KIM-1, short for Keyboard Input Monitor, was a small 6502-based microcomputer kit developed and produced by MOS Technology, Inc. ... The MOS Technology 4510 was the MOS-manufactured microcomputer chip used in the (unreleased) Commodore 65 8-bit home/personal computer. ... The 65CE02 (a derivative of 6502/65c02) is a CPU core developed by Commodore Semiconductor Group (formerly known as Commodore MOS) that has been used in the CSG 4510 micro controller (that combined a CPU and several I/O components) in the Commodore C64DX/C65. ... The 6501 is an eight-bit microprocessor, the first sold by MOS Technology. ... The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ... The 6507 is an 8-bit microprocessor from MOS Technology, Inc. ... The MOS Technology 6508 was an 8-bit microprocessor designed by MOS Technology. ... The MOS Technology 6509 was an enhanced version of the popular 6502 microprocessor, capable of addressing up to 1 megabyte of RAM via bank switching. ... Image of the innards of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). ... The Peripheral Interface Adapter (PIA) is a peripheral integrated circuit providing parallel I/O interfacing capability for microprocessor systems. ... Rockwell 6522 VIA The 6522 Versatile Interface Adapter (VIA) was an integrated circuit made by MOS Technology, as well as second sources including Rockwell and Synertek. ... Pin configuration of the 6526 CIA The 6526/8520 Complex Interface Adapter (CIA) was an integrated circuit made by MOS Technology. ... The 6529 Single Port Interface (SPI aka PIO) was an integrated circuit made by MOS Technology. ... The 6530 ROM-RAM-I/O-Timer (RRIOT) was an integrated circuit made by MOS Technology, as well as second sources such as Rockwell. ... MOS 6532 RIOT is integrated circuit which contains 128 bytes of RAM, timer and two 8 bit I/O gate. ... The Motorola 6845 (commonly MC6845) is a video address generator first introduced by Motorola and used in the CGA and EGA video adapters, Amstrad CPC and BBC Micro. ... The MOS 6551 Asynchronous Communications Interface Adapter was a simple UART chip produced by MOS Technology. ... The VIC (Video Interface Chip), specifically known as the MOS Technology 6560 (NTSC version) / 6561 (PAL version), is the integrated circuit chip responsible for generating video graphics and sound in the Commodore VIC-20 home computer. ... NTSC is the analog television system in use in Canada, Japan, South Korea, the Philippines, the United States, and some other countries, mostly in the Americas (see map). ... PAL, short for phase-alternating line, phase alternation by line or phase alternation line, is a colour encoding system used in broadcast television systems in large parts of the world. ... The VIC-II (Video Interface Chip II), specifically known as the MOS Technology 6567/8562/8564 (NTSC versions), 6569/8565/8566 (PAL), is the integrated circuit chip tasked with generating composite video graphics and DRAM refresh signals in the Commodore 64 and C128 home computers. ... MOS Technology SIDs: The right image shows a 6581 from MOS Technology, at the time they were known as the Commodore Semiconductor Group (CSG) and the left image shows an 8580 from MOS Technology. ... The 7360 Text Editing Device (TED) was an integrated circuit made by MOS Technology. ... The MOS Technology 8500 is an HMOS-II variant of the MOS Technology 6510 CPU used in the Commodore 64 computer. ... The MOS Technology 8502 was MOSs microprocessor used as one of the two¹ CPUs in the Commodore 128 home/personal computer. ... It has been suggested that MOS Technology 8568 be merged into this article or section. ... The MOS Tech 8568 VDU was the Visual (or Video) Display Unit controller chip responsible for the secondary (80-column or RGBI) display on the Commodore 128 personal computer. ... Agnus is the name of a range of custom chips that were featured in the Amiga home computer. ...

Notes

1. ^ Another theory on the calculator line drying up is somewhat more conspiratorial. It states that Commodore deliberately overbought MOS's chip line to monopolize it, and warehoused the extras. Then, with several months worth stored, they stopped buying anything and MOS's sales died. This forced MOS to sell to Commodore.^{[citation needed]}
2. ^ Phone conversation with Bill Mensch.

External links

• On the Edge: The Spectacular Rise and Fall of Commodore (2005) Variant Press, ISBN 0-9738649-0-7. – A book documenting the origins of MOS Technology and Commodore.
• Information on MOS' chips and their use in CBM's computers – By Ronald van Dijk
• EPA page on former MOS/CSG/GMT fabrication facility - link validated February 4, 2006

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. The Free On-line Dictionary of Computing (FOLDOC) is an online, searchable encyclopedic dictionary of computing subjects. ... GNU logo (similar in appearance to a gnu) The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free content, designed by the Free Software Foundation (FSF) for the GNU project. ...