Re: 6526 serial register

From: Mia Magnusson <mia_at_plea.se>
Date: Sun, 3 Nov 2019 09:23:19 +0100
Message-ID: <20191103092319.000061b7_at_plea.se>
Den Fri, 01 Nov 2019 14:11:18 +0100 skrev Michał Pleban
<lists_at_michau.name>:
> Hello!
> 
> Nate Lawson wrote:
> 
> > Yes, I implemented this mode for full speed SRQ nibbling in the
> > ZoomFloppy with a 1571. I clock data out at 2 MHz with the max
> > speed (500 Kbit/sec) as well as in from the microcontroller.
> > There’s a diagram with my oscilloscope showing this in this
> > presentation:
> > http://root.org/~nate/c64/xum1541/ZoomFloppy20100918.pdf It is
> > stable though we’ve occasionally found a few 6526A CIAs that would
> > get errors at this clock rate. The Amiga model seems to be more
> > stable for this.
> 
> Thanks! I will try the 500 kHz - 2 MHz range then to see what happens.

If you have the time, energy and equipment, it would be nice if you
could try messing with the timing at the higher frequencies. I.e.
delay the clock line with say a pair or a couple of pairs
of inverters. Repeat but with the data line. This test could give some
interesting information about the margins.



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Received on 2020-05-29 23:23:19

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