[A83] Re: LCD refresh rate
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[A83] Re: LCD refresh rate
At 20:47 2001-11-05, you wrote:
> >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?
>
>TO keep that nice black image, the LCD has to refresh every so often, or
>lock the image so you have to flash it to change the image (This is uncool,
>as it prevents any kind of animation, an dan odd strobing effect.)
To clear up some confusion (hopefully) the actual _image_ on the lcd is
ofcourse only updated when you write to the lcd (driver). What you do when
you run these functions for updating the lcd, is that you copy the image
from the graph backup or whatever the memory area is called, to the lcd
drivers internal ram, byte by byte, via the ports.
The lcd driver then reads from this internal memory to know which pixels
should be on or not.
This update of the actual lcd screen, is done all the time a lot, without
the z80 having to bother even one cycle to it. (no interrupts or whatever
needed)
The chip has its own built in oscillator that it can use. or can use an
external. (I don't know how the ti83 does it, probably uses the internal)
According to the datasheet (which can be found at
http://alh.dhs.org/ftp/calculator/ti83/tech/) the internal oscillator is
variable from 10kHz to 250kHz.
This is all leads I can provide.
///Olle
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