[A83] Re: lcdbusy

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: lcdbusy
From: "Gijs Leegwater" <g_leegwater@hotmail.com>
Date: Fri, 28 Dec 2001 18:05:40 +0000
Reply-To: assembly-83@lists.ticalc.org


The LCD driver needs +- 41 ticks between two OUT instructions. A good delay 
routine is:

delay:
      neg
      neg
      ret

But... when u have a fast loop or something in which the OUT instruction is 
used, it is stupid to use such a routine (more delay than needed). To 
optimize, count the clockticks that are in the loop between 2 OUTS, 
substract them from 41, divide by 4 and add that number of NOPS. e.g. u have 
a loop that is 30 clockticks between 2 OUT's then u have to add 4 nops to 
get 42 ticks.

-Cheiz


>From: "SUCKER from the old days" <sucker_pvn@hotmail.com>
>Reply-To: assembly-83@lists.ticalc.org
>To: assembly-83@lists.ticalc.org
>Subject: [A83] lcdbusy
>Date: Fri, 28 Dec 2001 16:41:53 +0000
>
>
>Do I have to a lcdbusy (or something similar) everytime I
>write directly to the driver, or only between two writes?
>
>        SUCKER
>
>
>
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