Question about UNTALK

From: Baltissen, GJPAA (Ruud) <ruud.baltissen_at_apg.nl>
Date: Wed, 29 Aug 2012 10:19:54 +0200
Message-ID: <219DEB1536CDE04E98DDD8620CA8CD68275E7A@winsv293.office01.internalcorp.net>
Hallo allemaal,
 
 
I first wanted to ask why on the C64 UNTALK is sent with ATN = (L) and
UNLISTEN isn't. Please see from $EDEF on. But then I noticed the JSR
$ED11 at $EE00. $ED11 first checks if there is a byte in the queue and,
if so, sends it first. Then it sets ATN (L) and sends the command byte.
So setting ATN = (L) at $EDF3 isn't needed anyway IMHO.
 
But what will happen now if a TALK needs to be sent and there is still a
byte in the queue? This byte will be sent with ATN = (L) and IMHO will
confuse the attached device ????
 
Any comment is welcome!
 
 
--
     ___
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   / /  |_/     Groetjes, Ruud Baltissen
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    \___|       http://Ruud.C64.org



  
 
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Received on 2012-08-29 09:00:04

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