Re: Broken TED for

From: Gerrit Heitsch <>
Date: Wed, 18 Jul 2012 18:13:07 +0200
Message-ID: <>
On 07/18/2012 03:22 PM, Segher Boessenkool wrote:
>> Hm, on the lower row of pads I find damage that looks very similiar,
>> just not as extreme though.
> I don't see anything like it?  At many places the metal is cracked and
> darkened, but near A7 it is totally black and not cracked.
> But who knows :-)

Could be... But what caused the driver for A7 to die in that fashion 
though? I should have tested all the signals before mailing in the CPU 
to see if any of them were dead.

>>> The driver structure for P5 is
>>> also missing; for the 8500 and 8502, this will have to be different.
> The drivers / latches for D and P are, top to bottom: 0 1 2 3 4 6 7 5,
> where that last one doesn't have the P stuff.  The lines coming from
> the core are swapped, and the lines going to the pads as well; it looks
> completely obvious that this is just a simple modification of the
> 8500/8502,
> which means that one is earlier.

If MOS stuck to the usual numbering scheme, it would mean the 8500 came 
first, at least as far as the design is concerned. Also, they did 
manufacture the 6510 and the 8500 in parallel for a while. I do have an 
8500 with a 1985 datecode and a few 6510 with 1986 datecodes. I wonder 
why they did it... Reliability issues that caused them to go back to the 
6510 until they were cleared up?

> These additions can easily be made to a 6502 to create a 6510, without
> adding a whole wide ring of stuff around it all, except obviously for
> the P port stuff itself.  The 850x is different of course, because the
> pad drivers have to be a lot bigger relatively.  So I'd still like to
> see what things look like on the 6510 :-)

I'd like to see the 8500 or 8502 first to see if it's really just a few 
minor changes.


       Message was sent through the cbm-hackers mailing list
Received on 2012-07-18 17:00:05

Archive generated by hypermail 2.2.0.