August 3rd, 2013 ~ by admin

MOS Technology MCS6501 Processor

MOS MCS6501 - November 1975

MOS MCS6501 – November 1975

One of the classic stories of the 1970′s microprocessor boom times was that of MOS Technologies at WESCON (Western Electronics Show and Convention) on September 16th 1975 in San Francisco.  MOS Technology was a newcomer to microprocessors.  They had with them two brand new processor design, the MCS6501 and the MCS6502 which they hoped to sell on the floor at Wescon, for $20 and $25 each.  However Wescon forbid sales on the convention floor, so quick thinking by MOS Technologies Chuck Peddle directed people to a hotel room, where “the beer was free and chips were $25.”  In the room were jars of 6501 and 6502 processors, to give them impression that these were in full production.  In reality the bottoms of the jars were filled with defective parts.  It was no matter, the 6500 series was a huge hit, led largely by its availability, low price and marketing to everyone (not just ‘big corporate users’).  The 6500, and specifically the 6501 have an interesting story leading up to that fateful day at WESCON.

Motorola XC6800B - July 1975 - Pre-production part, not something MOS bothered with.

Motorola XC6800B – July 1975 – Pre-production part, not something MOS bothered with.

It begins at Motorola, where Chuck Peddle, Bill Mensch and several others were employed in the early 1970′s design the MC6800 processor and its peripherals.  The 6800 was not a bad design, it was however, very expensive, a development board for it costing over $300.  Chuck worked largely as the 6800 system architect, ensuring all the ICs worked well together and were what was needed to meet customers needs.  He attended many calls to potential clients and noted that many were turned off by one thing, price.  With that in mind he sought out to build a lower cost version of the 6800 using some of the newer processes available (specifically depletion mode NMOS vs the enhancement mode of the 6800).  Motorola management wouldn’t hear it, they wanted nothing to do with a lower cost processor available to the masses.  And with that, Chuck, Bill and over half the 6800 team left.

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April 7th, 2011 ~ by admin

The Commodore is back!

Commodore USA has started taking pre-orders of its newly revamped Commodore 64 Home Entertainment system.   Of course this version comes with Blu-Ray and a dual core Intel (gasp!) processor running a version of Ubuntu Linux, it will include a Commodore OS 1.0 emulator, which should run all your favorite C64 6502 based games.

Commodore USA C64 - 1.8 Dual core Atom - 2GB RAM

The Original C64 had 64k of RAM, the Intel Atom D525 has 112k of just L1 cache.  At least the die size is similar :).
Commodore USA is also making modern version of the VIC computers for your enjoyment, albeit in slightly modified cases.

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Just For Fun

February 2nd, 2011 ~ by admin

How many Commodore 64 computers were really sold?

Production numbers of vintage technology have always been a somewhat mysterious subject.  How many 4004 processors did Intel actually make? I am not even sure Intel knows.  Unlike modern car companies who can track production numbers down to the shift of the day it was made, computer companies of the 70′s and 80′s were rather fast and loose with record keeping.

Thankfully with some research, serial numbers and some math (the famous tank equation) Michael Steil of Pagetable.com came up with what appears to be a very good estimate of Commodore 64 production.  12.5 million units, somewhat less then other numbers that have been thrown around, but backed by research and supported by math.  Read how he came to the conclusion here.

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Research

November 23rd, 2010 ~ by admin

Another Apple 1, Another Quarter Million Dollars

In September a Apple 1 computer with a few accessories sold for $23,000.  Christie’s has just auctioned off an early (first run) Apple 1, with invoice, shipping box, letter from ‘Steven Jobs’ and many accessories for a staggering $213,600.  This would have been one of the original PCB’s, sold without components and later assembled by someone else.  The main CPU is of course a 6502 but in this case a R6502P by Rockwell made in late 1981.

Complete Apple 1

What made this one so much more valuable?  The documentation and original box.  Whoever bought it should however replace the CPU with a white ceramic MOS 6502 to preserve the beauty of the original Apple 1.

September 27th, 2010 ~ by admin

Original Models: A Look at Iconic Tech Prototypes

Wired has an interesting article about several prototypes of rather historical devices.  Of much interest are the Apple 1, and the Atari 2600 although the doorbell powered Moog is pretty classy as well.

Take a look at the Atari 2600 prototype and notice that they used a MOS 6502 in it.  The final version used the lower cost (and smaller) MOS (or Synertek) 6507.

Atari 2600 Motherboard - 6507 CPU

When designing a product, it often is easier to use the standard full featured version of an IC for development work, and then as you refine the design, trim down to the least, and smallest components you can.

We also learn how Foxconn got its idea of low wages.  Steve Jobs himself paid his sister a mere $1/board to assemble the Apple 1.

Its interesting to see how prototypes can be so vastly different from the finished product.  A fact that design engineers know all to well. “I have to put all of THAT into what?”

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Just For Fun

September 20th, 2010 ~ by admin

Visual Transistor-level Simulation of the 6502 CPU

Here is an interesting project.  Take very high resolution photography of a MOS 6502 die (such as that the powered the Apple 1) and use it to construct a simulater in Java that allows you to program the 6502 and watch it, on a transistor level, as it performs the program.

6502 Die - Visual 6502

An awesome way to see PHYSICALLY what happens for each and every instruction.  And what a great processor to do so on.  Ironically the LCD flat panel monitor you may be using? It may well be powered by a 6502 (Novatek used them in their flat panel controllers)

Check it out at Visual 6502

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Posted in:
Just For Fun, Research

September 10th, 2010 ~ by admin

$23,000 for a 1MHz Computer – Only if its an Apple 1

A nice Working Apple 1 computer with much documentation was just (minutes ago) sold on eBay for $22,766.66.  Early computers (and the chips that make them work) are greatly increasing in value.  Especially if it happens to have the famous Apple name and customizations done by Wozniak himself.

Apple 1 Motherboard

The CPU on this board is a MOS 6502 in a beautiful white ceramic package.  It moved 8 bits of data at 1MHz.

MOS MCS6502 1976

Many other computers from the 1970′s are now worth thousands of dollars as well, such as the IMSAI 8080 and the Kim 1

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Processor News