Re: Re: a CIA riddle - please run these tests

From: peter_at_rittwage.com
Date: Fri, 19 Jun 2020 19:10:46 +0000
Message-ID: <b4cb479089471d8febfa74d3d07ee2ef_at_rittwage.com>
On Fri, Jun 19, 2020 at 01:03 PM, Spiro Trikaliotis  wrote:Hello Groepaz, 
* On Fri, Jun 19, 2020 at 06:35:07PM +0200 groepaz_at_gmx.net (mailto:groepaz_at_gmx.net) wrote:
Am Freitag, 19. Juni 2020, 14:16:11 CEST schrieb peter@rittwage.com (mailto:peter@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.
I am curious for that reason. Now, Arnd Menge was the one who wrote that SRQ code and is the mastermind behind it. I think he found the problem and fixed it some time ago, so he would know more about it. I will try to copy him into this conversation.
-Pete
Received on 2020-06-19 23:00:03

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