TI-H: Internal mem expander ANSWERS
[Prev][Next][Index][Thread]
TI-H: Internal mem expander ANSWERS
After reading the many letters concerning the expander, i have to
react. It appears that some of you claim it doesn't work, but have you
build it. Some ASSHOLE (danb) even claimed i've made this all up for
some attention. Well sorry, but i have enough attention. If there are
more of you that don't believe this works, they can stop reading now,
or come and visit me and look for yourself. Furthermore i could make
some pictures, but i doubt if that would convince some of you. For
those of you who do believe this might work, i will answer some
questions.
1. The memory that is doubled is 32k, but since the calc uses some
memory for the screen, there is 28k left.
2. There IS enough room for a second ic (if mounted on top of the
first.)
3. I read that someone wondered why i don't use the resistors in the
calc, or something, this is because there aren't any (well not for the
CS lines, anyway.)
4. Except for the resistors and the switch, there isn't any logic
needed for the expansion.
5. Grant said something about setup/down times, I don't believe it was
200ms, but even it it is, it still works.
6. When the calc is turned off, the memory provided with 5v, so it's
active if you look at it this way, but the processor isn't using it,
so even if you take out the ram ic it wouldn't matter to the calc (as
long as the ram ic has 5v to hold on to its data.) in contrary to a
dram ic, the data doesn't have to be refreshed constantly.
7. The circuit as i drew it, DOES work, so no changes are needed.
8. As mentioned in the docs, you need two resistors to pull up the
unused CS line.
At the moment this is all i can think off. I'm kinda busy right now,
but when i got some time left i will draw some nicer picture then that
ascii picture i drew. (I might even take a few pictures, although that
won't prove much.) Furthermore, if there are more people out there
that still don't believe me, i would rather have them to send an
E-mail directly to me. (this goes for danb and grant aswell (or did
any of you make this expansion))
A very pissed of member of the list,
Neil
_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com