MOS / CSG Commodore Semiconductor Group Timeline
Written by Ian Matthews of February 15, 2003

NOTE: Your are in the TEXT ONLY version of our site; click HERE to go to our full MOS Technologies / CSG page.

At the heart of what people think of as Commodore, was a company called MOS Technologies.  MOS developed and manufactured the 6500 line of processors which were used in nearly all of the non-Amiga Commodore machines and floppy drives. 

The Technical Manual for the 6500 and 6502 are available on our Gallery, Manuals page. The Technical Manual for MOS / CSG's number one product, the 6509 is available in the same location.  In September of 1983 Jim Butterfield wrote a nice summary of the 6503, 6504, 6505, 6506, 6507, 6509, 6510 (used in the Commodore 64), 6512, 6513, 6514, and 6515 chips for Compute magazine.  You can read his write-up clicking on the 6500 CPU's link on this page.  There are also history schematics, manuals available for the KIM1 on Gallery, Products, KIM1 page. 

Note that MOS Technologies Incorporated is wholly unrelated to MOSTek which was a 1984 Texas Instruments spin off.

August 1974
Eight Motorola employees including Bill Mensch and Chuck Peddle start MOS Technologies Inc.

June 1975
MOS Technology announces the MC6501 at US$20 and soon after the MC6502 at US$25. This was truly breakthrough pricing; the Intel 8080 costs about US$150
- MOS was able to produce the chips at this low price because they increased their yeild dramatically by reducing flaws in their chips 'masks' before starting production.
- Motorola sues MOS Technology over the similarity of the 6501 and 6502 processors to the 6800. In an out-of-court settlement, MOS Technology withdraws the 6501 from the market.
- About the same time MITS ships one of the first PCs, the Altair 8800 with one kilobyte (KB) of memory, as a $397 mail-order kit. The machine and company have nothing to do with MOS but it gives you an idea of what was happening at that time.
- The 6502 was not backward compatible with its Motorola 6800 inspiration and was upto 4 times faster.

Summer 1976
MOS Technology Inc. announces the KIM-1 Microcomputer System, with 1-MHz 6502 CPU, 1KB RAM, 2KB ROM monitor, 23-key keypad, LED readout, cassette and serial interfaces, for US$245.
- It was called a "Computer Trainer" but was largely designed as a demo machine for the MOS 6502 processor
- Chuck Peddle developed the PET concept and tried to sell it to Apple's Steve Jobs but Jobs did not offer enough  money for it
- Co-founder Bill Mensch leaves MOS for consulting work in Arizona.

September 1976
- Commodore announces it is buying MOS Technologies for US$60 Million so that it can become an almost completely self contained company.  Texas Instruments had provided processors for many Commodore calculators in the years previous and as Commodore made the business more successful, TI saw the opportunity.  TI stopped selling chips to Commodore and started selling Calculators directly.  Commodores supplier became Commodore's competitor and Jack Tramiel vowed this would never happen again.  Vertical Integration was the answer.

1976 - 1985
MOS / CSG designs and produces chip after chip feeding 100% of Commodore product like the VIC20, Commodore 64, Commodore 128, Plus/4 and many more 

MOS co-founder Bill Mensch starts the WDC Western Design Center and produce proprietery versions of the 6502.  About 2 BILLION 65C02 processors have been integrated into everything from cell phones to kitchen stoves since the 25 years since.   (Unrelated to MOS / CSG)

- Chuck Peddle leaves Commodore to work for Apple Computer and within months returns back to Commodore.

1985 - 1994
- Commodore starts to produce machines with Motorola chips (like the Amiga 1000, 500, CDTV...) but MOS / CSG is still a critical part of the Commodore machine

- EPA adds CSG's Norristown Pennsylvania fabrication facility to its list of hazardous waste sites needing cleanup after discovering extensive contamination from leaking underground storage tanks at the facility

- Under financial duress, Commodore closes its CSG Norristown, Pennsylvania fab
- Although the Commodore Semiconductor Group declared bankruptcy, the company continued to maintain the equipment and systems at the plant, ensuring that the facility would not fall into disrepair and would remain attractive to a potential buyer. 

1994 April 29th
Commodore goes bankrupt and the MOS / CSG remnants goes up for sale.

1994 September 2nd
- CSG is sold for US$4.3 Million to GMT Microelectronics Corporation (Great Mixed-signal Technologies) .

1994 December
- US Environmental Protection Agency opens discussions with GMT about the plant

- GMT experienced financial difficulties and the EPA shutdown GMT operations in 2001. GMT ceased operations and its semiconductor assets were liquidated.

- The EPA is overseeing the cleanup of the Commodore Semiconductor Group site. Construction of the groundwater extraction and treatment system began in the fall of 1999. In February 2000, pipelines and underground wiring were installed, pumps were installed at each of the extraction wells, and the treatment building was constructed. The treatment process equipment was installed in May 2000. Preliminary start-up and testing of the system began in August 2000. The system started operations in September 2000 to remove volatile organic compounds (VOCs), the chemical components of solvents and degreasers, from the groundwater using several filtration and evaporation techniques. The treated groundwater is discharged to the Audubon Water Company’s distribution system for public water.

Build Your Own KIM1

Click HERE for schematics and instructions to Build your own MOS / CSG KIM1 with components you can still find in 2003. 

Commodore Buys MOS Technology
Taken From the British Magazine "New Scientist" September 1976 Issue

"Commodore, the Canadian owned American based calculator manufacturer which markets under the name CBM in Britain, has announced its intention of entering integrated circuit component manufacture with a recent take-over. Unlike several of its competitors (such as Rockwell, National and Texas Instruments) who are primarily microcircuit manufacturers but who have also integrated vertically upwards into end-products like calculators, Commodore is integrating downwards in order to protect its supply of components.

Commodore, quoted at $60 million on the New York Stock Exchange, has acquired 100 per cent of the equity of MOS Technology Inc of Pennsylvania in exchange for a 9-4 per cent equity stake in Commodore. MOS Technology is privately owned and valued at around $12 million. It has an integrated circuit manufacturing plant in Valley Forge, Pennsylvania.

MOS Technology has been closely associated with Commodore for some years. The integrated circuit chip that went into CBM's successful SR36/37 calculator came from MOS Technology, as does the current chip for the SR7919D calculator (a model which is rumoured to have around 25 per cent of the UK scientific calculator market) and others of the current CBM range. But the firm not only makes integrated circuits for calculators, it has also lately launched a video game chip for four players and is currently marketing a successful microprocessor.

At present, Commodore produces the art-work for its calculator chips and subcontracts the chip manufacture to outside plants around the world with spare capacity. The recent purchase of factories in the Far East has enabled it to assemble electronic watch modules by this subcontracting method. But as the up-turn in the economy begins to effect the consumer electronics industry, less spare capacity is becoming available for this type of subcontracting. When considered along with the additional recent purchase of an LED display manufacturing facility, Commodore now has a completely integrated operation."

Commodore announces that the $495 PET (Personal Electronic Transactor) will be a self-contained unit, with central processing unit (CPU), random-access memory (RAM), read-only memory (ROM), keyboard, monitor, and tape recorder all in one package.

MOS's Secret Weapon

...In addition, MOS had a secret weapon, the ability to "fix" their masks. 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 chip will not work.

If a particular mask ends up with 10 flaws, there's no point in making another because it will have the same five design flaws, and some other set of five copying flaws. So you simply build with what you have, and throw away broken chips. At the time in the 1970's, this mean throwing away 70% or more of the completed chips. The price of a chip is largely defined by how many work, the yield, so improving this number can lower the price dramatically.

MOS 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. Their production lines typically reversed the numbers others were achieving, even the early runs of the new CPU design were achieving a success rate of 70% or better. This meant that not only were their designs faster, they cost much less as well.

When the 6501 was announced, Motorola launched a lawsuit almost instantly. 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...

Click HERE to go to our full MOS Technologies / CSG page.

Click HERE for a picture of MOS' / CSG's cement sign in front of their building


Site Meter