SDK-85 Cassettes

Last Updated or created 2023-10-24

Started drawing a Cassette interface in Kicad.
This so i can read back my old cassettes with programs.
(And write some new stuff)

I’m planning to buy a small micro cassette player.
With schematic below, I’m going to use it as save/load device.
But also with the same player, I’m going to convert the tape to a wave file, and try to decode the program using python.

While I’m at it, reading the old manuals, a RS-232 interface would be nice also!

UPDATE 20231016

This is the final version

Information about the 7655A.
A eprom WITH IO ports! Amazing piece of history hardware.

Testing some sims on Linux and Android

3 thoughts on “SDK-85 Cassettes”

  1. Hi Henri,

    I’m also busy on a cassette interface for the SDK-85.
    Made a print for it, need to test it shortly.
    If you like to have the Kicad schemes, mail me.
    On the website you can find a SDK-85 emulator I made.

    Best regards,

  2. Some notes from our emails:

    I can´t find my 8755, and don´t have a programmer for it.
    TI688II eprom programmer doesn´t work.
    Dirk has a ALL-11 programmer and managed to flash the chip.
    He offered to burn one for me, so i’ll make him a print.
    (He already has one, so he gets a spare)
    We tried to find a cassette Rom, but to no avail.
    But we got the source, so lets start typing (no way to ocr, scan quality is really bad)
    I found sources of my own programs and Martin.
    And a pdf about the BB-Board expansion. (with some schematics)
    Maybe i’ll add a potmeter for R15 before ordering the pcb’s

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