In JANUARY 1981, a handful of semiconductor engineers at MOS Technology in West Chester, Pa., a subsidiary of Commodore International Ltd., began designing a graphics chip and a sound chip to sell to whoever wanted to make “the world’s best video game.” In January 1982, a home computer incorporating those chips was introduced at the Winter Consumer Electronics Show in Las Vegas, Nev. By using in-house integrated-circuit-fabrication facilities for prototyping, the engineers had cut the design time for each chip to less than nine months, and they had designed and built five prototype computers for the show in less than five weeks.

What surprised the rest of the home-computer industry most, however, was the introductory price of the Commodore 64: $595 for a unit incorporating a keyboard, a central processor, the graphics and sound chips, and 64 kilobytes of memory instead of the 16 or 32 that were then considered the norm.

When the chip-development project started, the Commodore 64 was not at all what the designers had in mind. MOS Technology was a merchant semiconductor house.

At a meeting with Charpentier and Winterble late that month, Jack Tramiel, then president of Commodore, decided not to proceed with the video game. Instead, he decided, the chips would go into a 64-kilobyte home computer to be introduced at the Consumer Electronics Show in Las Vegas the second week of January 1982. The computer had yet to be designed, but that was easily remedied.

Following its enthusiastic reception at the Consumer Electronics Show, the Commodore 64 was rushed into production; volume shipments began in August 1982 and have continued unabated.

Despite complaints about quality control and the industry’s slowest disk drive, the Commodore 64 has been an unparalleled success

This Commodore 64 main board had so many things wrong with it, it was a fun challenge to get it working again. Previous owner(s) had caused damage to the board by removing chips, which adds an extra layer of difficulty to troubleshooting. It all starts with the dead test cartridge doing nothing.

In this video, I show my techniques for troubleshooting and fixing all of the problems.

Bad PLA chips (MOS 906114-01) are a super common problem for the “breadbin” Commodore 64 machines. There are replacements around but they aren’t that cheap. How about one you can build yourself at home for under $3?

The GAL-PLA has been tested on longboard PCB 326298, 250407, 250425 and the SX64 with no compatibility issues or modifications required. Tested with Super Zaxxon, 1541 Ultimate II and Easy Flash 3 with no issues on both NTSC and PAL machines.

0:00 – GAL-PLA Overview
10:57 – Testing the GAL-PLA with Super Zaxxon
13:45 – How to build your own PLA
25:43 – Cost breakdown of the GAL-PLA replacement

Arduino Emulates a Commodore 64!
https://m.youtube.com/watch?v=jMNXyMuxqfE

Arduino is actually powerful enough to emulate a C64. With only a few external components it outputs PAL or NTSC video and can be connected to any TV or composite input of an analog monitor.

0:00 Introduction
1:07 Emulation of the MOS 6510 CPU
1:40 Memory mapping: How 64 Kilobytes are squeezed into a Arduino RAM
3:17 Composite video output (VIC II emulation)
5:05 Connecting a USB or PS/2 keyboard and entering a simple BASIC program
5:57 Compare with the original C64
7:04 320×200 Hi Resolution mode on Arduino Mega

https://github.com/michalin/Arduino-C64-Emulator

Those of us who were around in the late 70s and into the 80s might remember the Speak & Spell, a children’s toy with a remarkable text-to-speech synthesizer. While it sounds dated by today’s standards, it was revolutionary for the time and was riding a wave of text-to-speech functionality that was starting to arrive to various computers of the era. While a lot of them used dedicated hardware to perform the speech synthesis, some computers were powerful enough to do this in software, but others were not quite able. The VIC-20 was one of the latter, but thanks to an ESP8266 it has been retroactively given this function.

SSSSAM
https://janderogee.com/projects/SerialSpeechSynthesisSAM/SerialSpeechSynthesisSAM.htm

If you owned a C64, an Atari or an Apple computer, then you might be familiar with the synthetic sound of the voice of SAM. The Software based text-to-speech speech synthesizer package that required no additional hardware. But if back then, you only had a VIC-20 then you missed out, because SAM won’t run on such a system, there simply aren’t enough resources, since the VIC-20 doesn’t have enough RAM. But the project on this page is about SAM and this project does work perfectly fine on a VIC-20 (and also on various other Commodore computers that have a userport).

…and that the Commodore 64 used the 6510 variant.