LZ: Re: Microwire
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>Does anyone have plans to interface the link port to a microwire bus
>with as few parts as possible? The prob with microwire is that it has=20
>an input and an output line instead of a tristate bidirectional line. =
There=20
>are 8 m-bit chips for microwire, (1 megabyte, cool)=20
>so if you just have one of those connected to the calc, your=20
>golden. I was thinking maybe using diodes to make the input and=20
>output line into a tri-state line?
I found that chip at the NSemi site today, and I must say that it has
awesome potentional. I assume you are talking about the National
Semiconductor parts. Since they are Flash EEPROM they will be a big
pain to write software for, but it will be well worth it (like you
said, 1 megabyte is more than cool). I'm not sure if you can make the
bus tristate with just two diodes, however. I can come up with a 2
bit input/output register circuit so that we can interface to the
microwire with about 2-3 small logic chips. If you have any other
suggestions that would be cool.
I've also come up (in case you haven't noticed) with an memory
expantion unit that uses standard NV RAM chips, but if there's a cheap
and easy source for the Flash chips (I haven't found any yet, although
I know they'll be less than $50-60$ for the 8M version), that will be
awesome. Also note that the chips are PLCC, which makes them an
absolute pain to solder to a board, but I think it's worth it.
As soon as I'm done reading the PDF file for the chips I'll design a
circuit for it.
BTW, the data sheets for the chips are at this location:
http://199.2.26.194/cadis/category.cgi?subclassid=3D1160
-CYA
-Mel
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