Re: A83: Two graphical problems to solve.

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Re: A83: Two graphical problems to solve.





>From: Martin Virt <martin.virt@gmx.at>
>Reply-To: assembly-83@lists.ticalc.org
>To: assembly-83@lists.ticalc.org
>Subject: Re: A83: Two graphical problems to solve.
>Date: Fri, 19 Jan 2001 19:13:10 +0100
>
>
>Hi!
>
> > The delay necessary depends on the calculator. You may be interested
> > in looking at the Ion library source (ionf.z80). I use a minimum of 65
> > clocks (total, not the delay routine), but that seems to still be too 
>fast
> > for some calculators.
>
>Thanks for the tip. I wanted to anyway (and now there's no excuse not
>to. (-: )
>Is it really calculator dependent or does that depend on the batteries?
>IIRC, in devices like Palms, calculator speed is related to the voltage
>of the batteries (and the oscillator, of course). Now assuming that the
>LCD driver's delay rate is constant, new batteries require a longer
>delay in the code, while those already in use may work just fine with a
>smaller delay rate.
>
>So 65 (perhaps even 70) clocks is a safe guess. Hmmm ...
>
>
>In any case, what happens exactly if the delay is too fast for the
>calculator?
>

If the delay is too small, then some 8x1 pixel chuncks get skipped.
This produces an ugly, inconsistant staircase effect.
(this was seen with ION 1.6 on a newer TI83, ROM 1.10, TI83+ style case)

>
> > And again, see ionf.z80. It certainly wouldn't be hard to port a TI-86
> > routine to the 83...
>
>Not this one. The Eble/Yopp routine benefits from from the 86's screen
>length of 16 bytes, and a neat trick with the RLD-Routine. There's no
>way this can be duplicated, as the 83/83+'s screen length is 12 bytes
>and therefore doesn't conform to nibble-boundaries. To be honest, I've
>already written a routine, but the ~160 clock cycles can't compare to
>the 127 of Ti-86's. I'd like to compare it to other routines in order to
>find anything that I may have overseen. (And I still have to test it for
>*possible* bugs...)
>
>Thanks again,
>               Martin
>

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