[A83] Re: LCD refresh rate
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[A83] Re: LCD refresh rate
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.
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
>