Re: sources of 6529

From: Rob Clarke <>
Date: Sun, 17 Jun 2012 17:47:41 +0200
Message-ID: <>
I disassembled large chunks of the 264 kernal last year when I built my 
diagnostic tool, and I'm pretty confident the kernal doesn't read it, 
but I do, simply to check it's operation. :-)

I've also had a couple of dead ones, but that's out of 20 boards or so 
and one of them I blew up myself. I have a pre-production +4 board where 
the key's on the user port edge connector have been cut back to front, 
so I plugged in the diagnostic harness upside down, sending 9v AC into 
places it was not designed for.  :-/

Much as the stamps with the Queens head printed back to front, I'm 
hoping to sell this board for about $1,000,000 and retire early. :-)


On 17/06/2012 17:34, Gerrit Heitsch wrote:
> On 06/16/2012 07:52 PM, Bil Herd wrote:
>> Yep, seemed designed for a whole byte of data in that number of pins. 
>> Kind
>> of glad they didn't try to embed more functionality by any kind of pin
>> re-use or processor controlled commanding, would have been harder to use
>> as a TTL'ish part.
> That reminds me... If I remember right, the 6529 used for the keyboard 
> port in the 264 series is only written to, never read (Correct me if 
> I'm wrong). That should make it possible to use a 74LS574 or the like 
> on a small adapter instead. Maybe with series resistors of a few Ohm 
> on the output pins. If I'm wrong an it's also read, it will be a bit 
> more complicated and need a bit of extra logic
> So far I haven't seen a dead 6529 anywhere, seems to be a very stable 
> chip, but it would be nice to have a generic replacement available.
>  Gerrit
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Received on 2012-06-17 16:00:26

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