Re: a CIA riddle - please run these tests

From: Spiro Trikaliotis <ml-cbmhackers_at_trikaliotis.net>
Date: Fri, 19 Jun 2020 19:00:23 +0200
Message-ID: <20200619170023.GF7337_at_hermes.local.trikaliotis.net>
Hello Groepaz,

* On Fri, Jun 19, 2020 at 06:35:07PM +0200 groepaz_at_gmx.net wrote:
> Am Freitag, 19. Juni 2020, 14:16:11 CEST schrieb peter_at_rittwage.com:
 
> What we are debugging there is the serial shift register and its interrupt,
> the tests puts data into the shiftregister to shift it out and then checks the
> value of the ICR at varying amount of cycles after that. The timing for the
> 4485 CIA seems to be shifted one cycle.

Now, that is interesting.

The SRQ nibbling in nibtools also uses the serial shift register of the
6526.

There are people who have problems and say it does not work.

Some of them have exchanged their 6526, and the problem vanished.

Reading this, I ask myself if this problem with SRQ nibbling might be
related. And that's most probably the motivation of Pete's question,
too.

You do not happen to have a variant of the test prog that can be run in
a 1570, 1571 and/or 1581? ;)

Regards,
Spiro.

-- 
Spiro R. Trikaliotis
http://spiro.trikaliotis.net/
Received on 2020-06-19 20:00:03

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