Re: CIA old/new?

From: groepaz_at_gmx.net
Date: Sun, 10 Jan 2021 22:42:54 +0100
Message-ID: <1652971.fL8zNpBrTj_at_rakete>
Am Sonntag, 10. Januar 2021, 22:39:18 CET schrieb Francesco Messineo:
> On Sun, Jan 10, 2021 at 10:32 PM <groepaz_at_gmx.net> wrote:
> > Am Sonntag, 10. Januar 2021, 22:19:44 CET schrieb Francesco Messineo:
> > > On Sun, Jan 10, 2021 at 10:08 PM <groepaz_at_gmx.net> wrote:
> > > > Am Sonntag, 10. Januar 2021, 22:00:53 CET schrieb Francesco Messineo:
> > > > > On Sun, Jan 10, 2021 at 9:58 PM Gerrit Heitsch
> > > > > 
> > > > > <gerrit_at_laosinh.s.bawue.de> wrote:
> > > > > > (*) I think only the 8500/6510 pair cannot be told apart via
> > > > > > software.
> > > > > 
> > > > > I have had success with this but I still need to make some other
> > > > > tests
> > > > > to have a reliable routine.
> > > > > I only have 2 x 8500 at home, so my sample size is very limited.
> > > > 
> > > > testing the bit fade time of the CPU port?
> > > 
> > > of course, I can't think about any other way.
> > > 
> > > This is a reliable indicator of die temperature, since gate leakage is
> > > function of the die temperature. It's very different between
> > > NMOS and HMOS-II. However I've found some broken 6510 that couldn't be
> > > tested (the "1" level fades before it can even be read
> > > back).
> > 
> > It's not reliable for telling them apart from my experience... you get a
> > quite high success rate, but still not 100%
> 
> my 8500 when very well warm are still slower than a very cold 6510, so
> my limited sample size is 100% reliable.
> However, I've also found the 6510 of some friends to give a bit too
> broad results.
> Of course the loop must run with VIC-II blanked and interrupts disabled.
> I have another idea about a test but I've never had the time to write
> some code for it. It would *maybe* work if the input gates
> of the bits 6 and 7 are very close in the die.

I tried it on ~10 C64s and two C128s... it would randomly give false results. 
The same is true for the bitfading on SID registers... you surely get a 
"typical" value most of the time - but not always. I wouldnt rely on it :)


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Die Furcht vor der freimütigen Antwort kann auch robuste Charaktere befallen. 
<Jeanette Schmid>
Received on 2021-01-10 23:01:31

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