[TI-H] Re: PIXpander

To: ti-hardware@lists.ticalc.org
Subject: [TI-H] Re: PIXpander
From: Adam Thayer <krevinek@matrix-z.net>
Date: Fri, 18 May 2001 16:57:20 -0700 (PDT)
Reply-To: ti-hardware@lists.ticalc.org




--- Olle Hedman <oh@hem.passagen.se>
>You know that the pic can run on a variety of voltages too? (2V - 6V)
>Maybe it is a good idea to run the pic at 3.xV?
>Nice work
>
>///Olle

(BTW, when you put 5V on a pin on a Mem Card, it dumps it out to ground and you end up with a 4.2V signal instead... showing that SOMETHING is not quite right... I get some severe problems with my Mega Memory Card while plugged into the PIC... I hope I haven't destroyed it though...)

Then you still have to run conversions for the TI calc... not a bad idea, but I can go out and get a Texas Instruments Quad Buffer that will do the trick for maybe a buck a chip. I read up the protocol stuff and it looks like the PSX uses an Octal buffer of the same make (since I just hook the SEL pin to ground, I don't need 5 pins) and did a nifty little pullup design. I should have actual schematic designs up tonight, and code up later once I test it all out. Trust me, when the final thing is released... it WILL work as intended, and have full 8x and 92(+) compatibility. I managed to realize how Sami did this: store the calc's code with the data, and just repeat the whole communication back to the calc when reading, making it think it is another calc of the same type. This also prevents people from accidentally sending an 83(+) game to an 86 or 89 at the same time, which I think is darn slick. Sami is a hell of a designer, just ran out of time to test/debug his design. 

-Krev

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