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:
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.