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Home-Brew Cassette Interface

PostPosted: Mar Fri 10, 2017 10:00 pm
by timali
I built my own cassette interface for my Micro-KIM using a novel design if anyone is interested. I had a hard time finding the ICs used in the original design, plus the original design required 12V, so I decided to redesign it and simplify it by using a single PIC microcontroller to replace the original PLL and comparator ICs. This allows the entire design to operate at 5V using a single IC and a handful of passives. It works very well, and it even supports all the HyperTAPE speeds, up to and including 6X speed. There is an LED indicator which shows you the quality of the input signal at all times, so you can use it to tune and tweak your cassette player/recorder for optimal performance. It can also store programs in the PIC's internal memory, and then play them back at 12X speed into the Micro-KIM at the touch of a button, allowing you to keep programs you use frequently stored directly on the cassette interface so they can be recalled without having to connect your tape player.

Here is a demo on YouTube:

I have about a dozen of these boards if anyone is interesting in building their own.

Re: Home-Brew Cassette Interface

PostPosted: Mar Mon 13, 2017 1:01 pm
by DixieGeek
Hi Tim,

This is a very cool retro project add-on.

Have you tested it with the other boards Vince produced for the Micro-Kim? Specifically the 32K Memory Card?

I'm interested one of the boards. Give me the details.



Re: Home-Brew Cassette Interface

PostPosted: Mar Mon 13, 2017 7:32 pm
by timali

No, I haven't tested it with any of the other official add in cards, because I don't have any. Electrically, I am confident it should work with the other cards because it only uses the TAPE and PB7 signals, which are essentially reserved for the cassette interface. Mechanically, it is possible it may not be compatible. I think the official expansion cards connect on their edges like PC motherboard expansion cards, while I designed mine to stack flat like pancakes. But maybe you can use a 90-degree connector to make the cassette interface play nice with the others and connect the same way.

If anybody is interested in the boards, while I have surplus inventory, I will happily mail one to you in exchange for the promise of eventually trying it out and letting me know how it goes. I can give you the schematic and BOM, along with the PIC source code. If you don't have the tools to program the PIC, I can send you one pre-programmed. Please note that I don't have any assembly instructions, so you'll need to use the schematic for that. Also, this is still very much a hack prototype, so don't expect anything as polished and professional as Vince provides :)

PM me if you are interested.

Re: Home-Brew Cassette Interface

PostPosted: Mar Tue 14, 2017 12:12 pm
by DixieGeek
I sent you a PM yesterday. Have you seen it?

Re: Home-Brew Cassette Interface

PostPosted: Sep Tue 10, 2019 11:52 am
by Paul Förster
Hi Tim,

can I buy this interface? I want one too. :D