Commodore 64

The MiSTer Commodore 64 core was derived from the works of Peter Wendrich of the FPGA64 project.

The Commodore 64 began its design life in January of 1981 when MOS Technology engineers decided they needed a new chip project. MOS’ Albert Charpentier had been responsible for several of the highly successful VIC-20 chips. “We were fresh out of ideas for whatever chips the rest of the world might want us to do. So we decided to produce a state-of-the-art video and sound chips for the worlds next great video game”.


By November of 1981, the chips were completed but Commodore’s president Jack Tramiel decided against using them in the faltering arcade game market.  Instead he tasked the engineers with developing a 64 kilobyte home computer for show at the Winter Consumer Electronics Show (CES) the second week  of January 1982; just 6 weeks away.

Two days after Jacks request, the basic design was completed and by the end of December 1981 the hardware for five VIC-30 (the C64’s development name) prototypes were assembled. In the remaining two weeks, the VIC-20 operating system with lowly Commodore Basic 2.0 was stretched onto the C64.  With an estimated retail price of just $595 ($1250 dollars in 2018), it was the buzz of the show.  It did not hurt that there were no other new powerful computers shown at CES by Commodores competitors that year.  The Commodore 64 was alive: it was immediately ordered into production which hit full stride by August 1982.

In addition to being vastly more powerful than anything on the market at the time, it was drastically cheaper than its competitors like the Apple II, IBM PC, or Radio Shack TRS-80. (Click the advert on the right.)

COMPUTERS FOR EVERYBODY, PRICED FOR NOBODY – C64 for under $600 – c64 compared to Radio Shack TRS 80, IBM PC JR, and Apple IIc – Compute! August 1983


The Commodore 64 is arguably the easiest to use programmable computer that has ever been made.  Like the PET and VIC-20 before it, the 64 booted to a friendly screen with the Commodore Basic Operating System ready and waiting for instruction.  If writing your own programs was too daunting and loading software from cassettes or floppies was ‘just too much’ for you, you could just jam a cartridge in the back of the unit and like magic your machine was doing whatever you wanted it to.

Creating the best selling machine in history is no small feat.  Commodore did not ‘knock the ball out of the park’, they ‘knocked the park into the next city’.  The pushed the industry to a level of scale that was previously thought impossible.

Like its VIC-20 predecessor, the 64 was the first computer that millions of today’s programmers, designers, engineers and enthusiasts had ever used.  It has inspired a countless volume of software and hardware that we use today.

The Chips:


In 1980 Commodores semiconductor arm, MOS Technologies, completed development of the 6510 Central Processor and chip set.  It was a standard  .9875 MHz  6502 (used in the KIM-1 and PET) with a additional input/output port and  the ability to see allot more RAM.  As part of the “next great video game” concept, Albert Charpentier recruited another MOS engineer Robert Yannes in 1981 to help figure out how far other companies could push their current technology.  By their own admission, they pulled apart and ‘stole’ ideas from Texas Instruments TI 99’s, Atari 800’s, Apple II’s and others.  It is worth noting that most computers of the day used Commodore / MOS’ powerful but inexpensive 6502 processcor

According to Charles Winterable, Commodore’s  Worldwide Engineering Director, “We defined in advance the die size that would  give a yield we were willing to live with.  …Then we prioritized a wish  list of what needs to be in there to what ought to be in there to what we  would like to be in there.  …When he ran out of registers, he stopped.”  With two draftsman and a CAD technician they developed “first silicon” in just 9 months and shockingly it worked on the first try.

The VIC-II 6567 video chip in the 64 can produce about 128 colours but was only engineered for, and only officially supported, 16 colours.  “The width of each pixel is almost half of the NTSC colour clock, so when you alternate the pixels of two different colours, instead of getting the two colours that you think you’re getting you get a whole new phase interpretation”  Brian Dougherty, President of Berkley Software explained.  It displayed a large 320 x 200 character count.


The now legendary SID 6581 sound chip was astounding for its time.  It could play three different “voices” in sophisticated patterns and with some tinkering could be made to create one or two more.  It was without doubt the best sounding computer on the market at any price for years to come.  It was also likely the first computer in the world capable of reproducing a recognizable human voice without  the addition of peripheral hardware.

The most common C64 chip question is why does the screen say 38,911 bytes free when it supposedly has 64,000 bytes of memory.   This is because nearly half of its memory is used for internal functions like Commodore Basic 2.0  (a.k.a. Microsoft Basic). .

Author: Admin