TI-H: TI-85 schematics, CHECK THEM OUT!!!
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TI-H: TI-85 schematics, CHECK THEM OUT!!!
I'm sorry everyone. I'm such a moron. I was so hurried to get the
schematic posted that I completely forgot to include my web page
address.
It's http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html
I'm sorry about that! (25 hit have already been made since I posted it
at 2:30, even without my page address posted! Seems to be a thing to
see!) As for Osma's remark, I do intend to clean it up. I'll make a true
schematic (actual symbols instead of pictures. I'll keep the symbols in
the layout they're in now though, so It'll be easy to decipher. I may
also rotate the schematic so it is vertical like the actual board. I'll
make it very nice, but it'll be a little while yet. I don't think it is
100% complete, and I want to finnish completely before I continue with
minor things like cleaning it up. I may procede with other models when
I'm completely finnished with this one. If anyone has pin charts for the
memory chips in any calc, I'll need them to identify R/W lines, data bus
lines, an the address lines. Power and link circuits are easy. The
busses are tedious due to numbers, but simple when it comes down to it
since there are no complex or straying connections. The keyboard was
hardest since it requires messing with both sides o he board at once,
but even that was only a 2 hour job.
I'll accept dead circuit boards of any calc as well cause I realy don't
want to take apart any of my good calcs. I'll probably do the TI-82
next, since I have a dead TI-82. The TI-82 will be almost twice as
difficult. It has 4 chips and twice the discrete components!
The TI-92 will be hell and the TI-83 and 86 use newer technology and
they realy pack their components!the TI-80 is even a stuffed little
calc. The only calc that'll be easyer to do will be the TI-81. Part of
the reson the TI-80 is more difficult is that link circutry seems to be
built in. The parts are just not soldered on. It looks like the TI80
should have a view screen and a link port both, so I'll map both out as
well. Maybe we can some how make the link port and hope the TI-80 can
some how support silent linking. Imagine if it could!
Oh well, for now we can just stare at the TI-85 schematic. Maybe
someday!
By the way, does anyone know how to replace an R/C (resistor capacitor)
network with an xtal or resonator. Maybe we can make a REALY high speed,
accurate clocked, TI-85! Also, if the transistors are identified, and
maybe replaced with high speed video transistors, maybe the link port
could be brought up to speed. Also, if the 4 ports Mel Discovered are
ever solved, an internal memory expander could be made, like he
mentioned! A high capacity capcitor to replace or supliment the backup
battery, a reset switch, interupts??? Dirrect bus access??? Who knows!!!
Richard Piotter
richfiles1@hotmail.com
>
>
>I'd love to take a look, but what's your web page address (i missed it
if
>you posted it beofre).
>
>- Jon Olson
>
>-----Original Message-----
>From: Richard Piotter <richfiles1@hotmail.com>
>To: ti-hardware@lists.ticalc.org <ti-hardware@lists.ticalc.org>
>Date: Monday, February 02, 1998 4:45 PM
>Subject: TI-H: TI-85 schematics, CHECK THEM OUT!!!
>
>
>>
>>Mel Tsai gave me his incompleted TI-85 schematic. I finnished up the
>>power circuits and keyboard. There are a few processor pins not
>>connected yet, but they will be added soon. I just need some strong
>>solvent to eat away the paint on the circuit board so I can get the
the
>>wires. Should be 100% done very soon! There are even DATA and ADDRESS
>>bus pins marked!!! This means DIRECT BUS ACCESS may be in the
forseable
>>future!!!
>>
>>Go to my web page to see the shematic. It takes a good 50K, so I'm not
>>attaching it. I tried but it never would send. Just scroll down in the
>>news & updates section and it'll be the first item. It will definitely
>>be up by 2:00 PM Central time!
>>
>>I'll also clean it up some day as well!
>>
>>Hope you enjoy!
>>
>>Richard Piotter
>>richfiles1@hotmail.com
>>
>>>
>>>Hey, I finally remembered to scan the stuff in. It's very crude and
>>>will probably take you a while to figure out what was drawn, and it's
>>>incomplete as well.
>>>
>>>I've also included the schematic for the internal AT45D041 schematic
>>>using the four 'ports' (actually it only uses three). The
programming
>>>of these ports takes quite a bit of experimentation and detailed
>>>observation of what's going on... I don't have time to explain it.
>>>But you have it.
>>>
>>>-Mel
>>>
>>
>>
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>>
>
>
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