Re: TI-H: General questions with a possibly big impact.
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Re: TI-H: General questions with a possibly big impact.
kaus@cybrzn.com wrote
> Alright. These questions are about the internals of the TI-85
> calculator. if things turn out, it could be a huge thing. I don;t know
> if they would be the same on the other calcs, but it is very likely.
>
> Anyone of the questions you can answer would be very helpful:
>
> 1) Is the RAM on the calc Dynamic or static?
It is static, definitely. Dynamic RAM requires a constant refresh, and
as such you'd get maybe 30 seconds out of a pair of AAA batteries :)
> And, is the EIII doen yet? where can i get information on the EIII (or
> EII or whatever you want to call it)
I am going to begin shipping programmed E2 AVRs at the beginning of
next week. If you'd like to build your own E2, check out the home
site at http://www.flash.net/~bryanr/eii/ (I took over the project
from mel, who up until two days ago was wisely out of this profession)
:)
> Thank you for everyone that can help me with any of these questions.
> Towards the end of the main questions, who may have glimpsed waht i am
> aiming at with these things, but if not, here it is:
> All the current expanders and communications networks are slow by
> definition, because they must operate throught the serial interface
> provided by TI, or another serial interface (such as the SPinTerface
> Port). If these questions turn out the way i want them to, we could
> have infinite IO devices operating at 8bits. they can work at processor
> speed and do whatever we want. Anything is possible with this. I hope
> you see the ramifications of this power, but if not, please try to
> answer any of my questions that you can anyway, jsut to help me in my
> quest. Thank you again for any help you can give me,
It would allow very high speed memory expansion, but there are two HUGE
disadvantages: it would not be easy to move the device from one
calculator
to another, and if the calculator crashes you lose everything stored in
the SRAM -- unless you get a more expensive battery-backed SRAM. Also,
nearly noone wants to take their calculator apart for such an elaborate
hack, indeed, not very many people, as mel said, have the ability or the
tools to work with the delicate chips and extremely small pin spacings.
The E2 gets about 4k/sec on the TI-92 and will probably get about that
on the TI-8X... seeing as how the calculator programs are so small,
speed
is only a very small issue. The link port is easy and quick to connect
to, and it does not require any modification of the calculator
whatsoever.
Both methods have their advantage, to be sure, but I still think an
external device is perfectly suitable for memory expansion.
Regards,
Bryan
--
Bryan Rittmeyer
mailto:bryanr@flash.net
http://www.flash.net/~bryanr/
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