Calculators, codes, and hidden messages

by Leonard Tramiel

Looking at a list of the chips used in Commodore calculators we see some letter and number combinations that are quite meaningful, if you know the stories.

Some of the most sophisticated processors that Commodore made were based on a custom chip set that used a common processor and different ROMs (or two) that contained the code for that particular model. I wrote the firmware for a few of those. Like this one:

Photo credit: Dave McMurtrie
One of my favorite memories is the way those ROMs were programmed, as described here. This processor was a fully custom chip and it required a LOT of engineering work, time, and money. When my father, Jack Tramiel, was persuaded to approve the project he told the person in charge "God help you" if this doesn't work. The chips all have product names the contain GHU for God Help Us.

The first set of calculator chips that Commodore engineers developed included as much of the circuitry as thought possible into a single chip. This allowed the calculators to be produced at a Rock Bottom Price. These contain RBP in the product names.

The RBP calculators consisted of little more than an LED display, a few resistors and capacitors, a battery, a keyboard, and two chips. One of those chips contained all of the logic to perform the calculator functions. The other chip was only needed to drive the LED display. Without getting into the details of n and p channel semiconductors and the details of LED displays, the technology of the time required this extra chip. Or so it was thought. Then a Commodore chip designer realized that by changing the way the LED display was wired that display driver could be eliminated. This allowed a significant cost saving by using a Direct Drive Display. These chips named contain 3D. 

It was certain that when the 3D chip based calculators were produced the chip would be opened up and analyzed. The earliest version of those chips (possibly later ones as well) had a message in one corner. The letters FKU.

Popular posts from this blog

If Looks Could Kill

by Leonard Tramiel At one of the many computer trade shows over the years I had a really funny interaction with Bill Gates. I was doing demos on the PET and answering the questions of those that walked by. I noticed a large group of people approaching, but at first I didn’t recognize anyone. As they got closer I saw that it was Bill Gates leading the others around. There was a translator repeating what Bill said into Japanese. When they reached me Bill walked up to a PET and typed WAIT 6502,10. This caused the machine to hang and he froze. I said, quietly enough in the loud hall that only he could hear, “Bill, there’s nothing at 6502 so that’s just going to freeze”. He turned and gave me a look that was a perfect example of a look that could kill. I knew what he was doing so I turned to the group and said something along the lines of, “Microsoft BASIC is a valuable part of this machine”. Bill relaxed and the group left the suite. The WAIT command in Microsoft BASIC was an unusual addit
Read more

Creating PETSCII

Image
by Leonard Tramiel When Chuck Peddle was given the go ahead to bring his ideas of what would become the PET computer into reality many of the ingredients were only loosely constrained. One example is the character set. It would clearly need to have alpha-numeric characters and the basic punctuation. But that was far  too limiting for many recreational uses of the machine. It should be possible to create a set of graphics characters that would allow a wide range of images to be created yet still have the hardware simplicity of a character based system. He knew that one of the likely uses of the computer was going to be card games. The game of Blackjack was a favorite of both Chuck and my dad. That meant the only thing that was well defined about the set was that it needed to have the four suits; hearts, clubs, spades and diamonds. He gave me the task of designing that character set. Each screen location would store an 8 bit number, 256 possibilities. The top bit would swap on and off pi
Read more