Re: A83: OT: Off topic, but interesting


Re: A83: OT: Off topic, but interesting

In accordance with the prophecy, Nathan Gaylinn uttered:

> Linus Akesson wrote:

>> In accordance with the prophecy, Nathan Gaylinn uttered:
>>> Linus Akesson wrote:
>>>> In accordance with the prophecy, Nathan Gaylinn uttered:
>>>>> Is it possible to have a rom chip w/ the same i/o set up as the ram chip
>>>>> in a TI calc? What changes would have to be made? I know this is out
>>>>> there, but the implications are wonderful, a plug in cartridge w/ an
>>>>> entire calc's ram stored in it permanently! Is this possible? Has this
>>>>> been considered before? I want input. What do you guys think?
>>>>> --
>>>>> "What, behind the rabbit?"-King Arthur
>>>>> The Heat Index
>>>>> (\\_
>>>>> o(_;
>>>> Am I getting this right? Are you suggesting a ROM chip for $8000-$ffff?
>>>> Because how would you be able to use your calc without RAM? And even if you
>>>> had RAM installed at all the fixed RAM locations and ROM in user space, you
>>>> wouldn't be able to calculate anything on the home screen, because where
>>>> would the input buffer go? And the floating point / operator stacks?
>>>> "Memory is necessary for all operations of reason."
>>>>                                    -- Blaise Pascal
>>>> Linus
>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>>>>    "Television has changed the American child from in irresistable force
>>>>    into an immovable object."
>>>>                                                     -- Laurence J. Peter
>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>>>>, visit (PGP key available).
>>> No, that's not quite what I mean. I know the calc needs the ram, what I am
>>> suggesting is completely replacing the ram chip w/ a comparable rom chip (if one
>>> exists) so that all the normal functions of the ram are carried out on the new
>>> rom and all the normal old rom functions still happen on the old rom. I have NO
>>> idea if this is possible, so don't go yelling at me saying "You can't do that!"
>>> Because I just don't know, it's just a thought.
>> Well, I wasn't yelling, really... =) But are you refering to some kind of
>> non-volatile RAM? A chip with, say, 32 different banks of 32kb RAM, one of
>> which can be available to the calc at a time. Then you'd be able to turn off
>> your calc and switch to another bank. You wouldn't be able to share or
>> transfer anything between the banks through the calculator though, you'd have
>> to link cable transfer stuff into the correct bank every time.
>> Linus
>> ----------------------------------------------------------------------------
>>             He may look like an idiot and talk like an idiot but
>>             don't let that fool you.  He really is an idiot.
>>                                                  -- Groucho Marx
>> ----------------------------------------------------------------------------
>>, visit (PGP key available).

> That is EXACTLY what I'm talking about! I just don't know if it will work!

Well, theoretically. There is a pin on the ram chip (IF there is a standalone
RAM chip in the calc, but there probably is) called Chip Enable. If you take
31 ram chips and connect them in parallell with the original one except for
this Chip Enable connection, and lead the outgoing Chip Enable signal from
the processor to some kind of switch with 32 states, you can have 32 lines
going out from the switch and into the different memory chips. Whenever the
switch is in a certain RAM chip's position, it copies the Chip Enable signal
from the processor to the RAM chip. All other RAM chips get a logcal zero on
their Chip Enable pins.

                    Tragedy is when I cut my finger.
            Comedy is when you fall into an open sewer and die.
============================================================================, visit (PGP key available).

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