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From: griff@anvil (Richard Griffith)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: NEC 2A question
Message-ID: <1990Dec7.154431.1952@intelhf.hf.intel.com>
Date: 7 Dec 90 15:44:31 GMT
References: <1990Dec5.155357.3957@intelhf.hf.intel.com> <16335@cbmvax.commodore.com>
Sender: news@intelhf.hf.intel.com (News User)
Organization: Intel Development Tools Operation, Hillsboro, OR
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Nntp-Posting-Host: anvil.intel.com

In article <16335@cbmvax.commodore.com> raible@cbmvax.commodore.com (Bob Raible - LSI Design) writes:
>In article <1990Dec5.155357.3957@intelhf.hf.intel.com> griff@anvil.intel.com (Richard Griffith) writes:
>>How difficult is it to hook up a NEC Multisync 2A to a 2000?
>>anyone know? (awww, comeon, someone here knows... :-)                   
>>               
>>                       - griff
>>
>>:Richard E. Griffith, "griff" : iNTEL, Hillsboro Ore.
>>:griff@anvil.hf.intel.com
>>:SCA!: Cyrus Hammerhand, Household of the Golden Wolf, Dragons' Mist, An Tir 
>>:These are MY opinions, if iNTEL wanted them, They'd pay for `em!
>
>I currently use this combination at work. As you note I am a chip
>designer and not  an official spokesman for this type of thing, so I am
>not certain as to what the "official" advice is. What I have noted is
>that if productivity mode operation is desired(when 2.0 is available to
>2000 owners) then it is necessary to use separate syncs and not the
>CSYNC signal. However during boot phase HSYNC and VSYNC outputs are
>momentarily tri-stated and checked for the presence of an external
>source of syncs(genlock). However presence of 75ohm pulldowns on NEC2A
>sync inputs, the levels are less than ideal and the software wrongly
>concludes that an external device is trying to supply syncs and will
>provide synchronized 28MHz as well. Consequently the internal 28MHz
>clock is disconnected and the system hangs.
>
>The upshot of the above discussion is that ideally the hsync and vsync
>signals will be buffered before being connected to monitors having 75ohm
>terminations. Typically a TTL buffer is wired into the hood of the
>B2000 video connector. The other alternative is to use CSYNC instead,
>but as mentioned above, CSYNC won't be available when using any of the
>new ECS programmable modes(640x400,1280x200 noninterlaced).
>
>Hope this helps - sure beats trying to figure out why your new monitor
>keeps causing your 2000 to hang!

hanging? are we talking about the same article?  I haven't yet
hooked the 2a up yet (does the above tell me that this is a little 
tricky?) 

                                       - griff





















-- 
:Richard E. Griffith, "griff" : iNTEL, Hillsboro Ore.
:griff@anvil.hf.intel.com
:SCA!: Cyrus Hammerhand, Household of the Golden Wolf, Dragons' Mist, An Tir 
:These are MY opinions, if iNTEL wanted them, They'd pay for `em!