September 21, 2023

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Producing A Cassette Mass Storage Interface

If you are of the technology who had been fortunate enough to use the 1st 8-little bit house desktops in your youth, you will be acquainted with their use of cassette tapes as mass storage. Serial knowledge would be transformed to a sequence of tones which could then be recorded working with a conventional domestic cassette recorder, this recording could then be played again into the machine’s decoder and loaded into memory as a complete piece of software program. Bigger plans could consider a whilst to load, but while it was instead clunky it was a masterful piece of earning the best of what was at hand.

[Mike Kohn] was doing the job with some microcontroller infra-crimson conversation projects when he noticed that the very same techniques could be made use of to deliver a tape interface like these on the dwelling computer systems of aged.

More than the a long time he has returned to the undertaking a few of occasions, and his authentic Atmel processor has been supplanted by a W65C265SXB advancement board primarily based on the 16-bit derivative of the 6502. This created generating the tones as clear-cut making use of his processor’s constructed-in tone generator, but decoding however presented a obstacle. His previously makes an attempt utilized an LM2917 frequency to voltage converter to decode tones to logic ranges, but on further more thought he resolved to go to the LM567 tone decoder. This chip is created specifically for an on-off logic output alternatively than the 2917’s analogue voltage output.

His recording device was at first a hello-fi individual cassette deck soon after experimenting with microcassettes, but ultimately he employed a facts recorder developed for a Radio Shack TRS-80. All his code can be found in his GitHub repository.

It’s likely legitimate to say that [Mike] has built a improved cassette interface than the a person you could have located on your residence personal computer again in the working day. We have highlighted a handful of data cassette hacks more than the several years, together with this Commodore tape deck with an LED counter, and a tape deck emulator able of holding an total software archive.