[A83] Re: LCD refresh rate
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[A83] Re: LCD refresh rate
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Original Message
From: "Tijl Coosemans"<tijl.coosemans@student.kuleuven.ac.be>
Subject: [A83] Re: LCD refresh rate
Date: Thu, 1 Nov 2001 16:02:09 +0100
>
>Good question. I think nobody really knows the answer. Just a few
>speculations...
>
>An LCD must refresh otherwise it just fades out. On the 85/86 that refresh
>rate is steered by the interrupting device. Every two interrupts, the LCD
>gets updated. The first interrupt notifies the LCD chip and the second one
>actually makes it update itself (or something like that, don't quite
>remember).
>
>One of the main reasons why it works that way on the 85/86 is that, if you
>speed up interrupts (by using the proper ports), the LCD gets darker. Also
>(if I got that straight), while your batteries run out, the interrupt
>frequency increases, which indicates that there must be something that
>regulates this. I don't know what effect increasing the contrast has over
>interrupt speed.
>
>On the 82/83/83+/83+SE things are different (what else did you expect :-).
>Since these calcs come with an LCD driver (from another company than TI;
>think it was Toshiba, but don't quite remember that either), it is expected
>that it has its own refresh rate regulator. And indeed, if you speed up
>interrupts on the 82/83-series, it gives no noticeable effect on the
>contrast. Moreover, the interrupt speed decreases while your batteries run
>out.
I thought the LCD was only refreshed when you actually wrote stuff to the
LCD ports - is the LCD driver just updated when you do that?
Is the LCD driver really continuously refreshing the LCD? Like it has
it's own interrupts or something?
>So, as you can see, it is difficult to tell what the exact refresh rate of
>the LCD is on the 82/83-series. I guess it's about half of the interrupt
>speed, but if you really want to know, I think you must ask TI or Toshiba.
>
>Tijl Coosemans
>
>>
>> From: "The one and only SUCKER ..." <sucker_pvn@hotmail.com>
>>
>> What is the refresh rate of the LCD, or the Mhz of the LCD
>> driver/chip???
>>
>> SUCKER
>>
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