Re: TI-H: DriverLESS Memory Expander

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: DriverLESS Memory Expander
From: gussie@alaska.net (Grant Stockly)
Date: Mon, 17 Nov 1997 16:06:20 -0700
Reply-To: ti-hardware@lists.ticalc.org

>At 08:59 PM 11/16/97 -0700, Grant Stockly wrote:
>
>>Well, that wouldn't add more than about 32k.  The rom in the calcs doesn't
>>even support more than that.  It would take a long time, and your warntee
What I meant to say, was that the calc doesn't support more than the
orrigional 32k (27.5k) and adding more is impossible.

>>would void.
>>
>>>what about adding directly to the existing memory in the calc so that it
>uses
>>>the existing MAP.?  Im surprised nobody has devised a lan to take care of
>>>that.
>
>Actually it would be impossible.  The ROM is addressed in from $0000-$3FFF
>for page 0 and $4000 to $7FFF for pages 1 to 7.  The RAM is addressed from
>$8000 to $FFFF (including stack and video mem).  Because the Z80 can only
>use 16-bit addresses that's all the memory it can address.  The TI-86 uses
>RAM pages, but this would be impossible on the 85 because even if you added
>it, the ROM wouldn't support it.
>
>
>--
>Brian Leech
>butvis@mindspring.com
>ICQ UIN: 1355611

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Re: TI-H: DriverLESS Memory Expander

From: tsaimelv@pilot.msu.edu (Mel Tsai)

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