A89: Re: TI-89 LCD Driver

To: <assembly-89@lists.ticalc.org>
Subject: A89: Re: TI-89 LCD Driver
From: "Josh 'Gage'" <antgage@apk.net>
Date: Wed, 8 Nov 2000 21:38:26 -0500
References: <20001109022734.6416.qmail@web1704.mail.yahoo.com>
Reply-To: assembly-89@lists.ticalc.org


lots of technical information crammed into two paragraphs.

I love this mailing list :)
----- Original Message ----- 
From: "Jeff Flanigan" <propalo@yahoo.com>
To: <assembly-89@lists.ticalc.org>
Sent: Wednesday, November 08, 2000 9:27 PM
Subject: A89: TI-89 LCD Driver


> 
> I have a few questions about the LCD driver for the
> 89.  Maybe some of you know the answers or maybe I
> will just have to try some tests.  
> 
> I assume that the driver doesn't use built-in graphics
> RAM, because if it did then grayscale wouldn't work. 
> Therefore, it must use the RAM that it is assigned to
> draw its image from, and not mask over it.  Does it
> use bus mastering to read the RAM, or what?  How much
> time does an entire read take?
> 
> Can the address it draws its image from be in the
> flash ROM area?  Do its reads to the RAM or ROM go
> through the U8 chip that controlls flash protection? 
> Is this why the TI-OS disables LCD update when
> unprotecting the ROM?  Maybe the LCD reads can be used
> to unprotect the ROM on any current or future AMS. 
> Just some food for thought.  :)
> 
> - Jeff Flanigan
> 
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References:

A89: TI-89 LCD Driver

From: Jeff Flanigan <propalo@yahoo.com>