Reliving 1977’s cutting-edge computer with the Pocket Mini Computer

Classic computers are just up [Jeff]’s alley, so when he looked for a new project for his Pocket Mini Computer, he looked at one of the earliest microcomputers available: the COSMAC VIP, a 1.76 MHz beast from 1977.

The COSMAC VIP was a single-board educational computer released by RCA in 1977. Priced at just a hair under $300, the COSMAC was much more affordable than infamous $1300 ‘fruit’ computer also released that year. To get young programmers up and running quickly, the COSMAC came bundled with the CHIP-8 programming language, making it very easy to generate graphics on-screen for all the eventual PONG and Breakout clones.

[Jeff]’s COSMAC VIP runs on a Pocket Mini Computer, a very cool Parallax Propeller-powered board we’ve seen before emulate other retro computers including the venerable Commodore SID synthesizer┬áchip.

Because the COSMAC’s user interface was the very, very old-school 4×4 hexadecimal keypad, [Jeff] found it necessary to emulate this retro feature by soldering his own 4×4 keypad. After soldering 16 buttons into 8 columns and rows, [Jeff] connected this keyboard to a PFC8574a I2C I/O expander and connected this chip to the I2C bus on the Pocket Mini Computer.

The result is an emulated COSMAC VIP that’s just begging for an ‘introduction to microprocessors’ class or just a round of Tetris, Tic-tac-toe, Lunar Lander, or one of the several Breakout clones available for this very cool computer. A pretty awesome build, even if it is from the dawn of the computer age.

Creating a MIDI synth from a Commodore SID

The Commodore SID was the audio chip in the venerable Commodore 64 and in the 30 years since release has attained classic status and become one of the best ways to get your chiptune on. Designed by famous synthesizer designer [Bob Yannes], it was only a matter of time before we saw a real, homebrew MIDI synth based on the Commodore SID.

Because real SID chips are rare as hen’s teeth nowadays, [Jeff Ledger] built his SID synth around an emulated system running on a Pocket Mini Computer. This very cool microcontroller platform runs on the Parallax Propeller. An emulated SID runs in one of the Propeller’s 8 cores, with the remaining cores kept open for reading MIDI notes and displaying info on a display.

The hardware portion of this build is amazingly simple; just an optoisolater, a few resistors, and a diode connect a MIDI keyboard to the Pocket Mini Computer. The buttons and dials on [Jeff]’s MIDI keyboard control the waveforms, filters, and envelope controls. A very neat setup if we do say so ourselves, and just perfect if you’re needing more chiptunes in your life.

You can check out [Jeff]’s video after the break.

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