Re: Plus/4 RS232 woes

Den Tue, 4 Sep 2018 18:34:08 +0200 skrev Gerrit Heitsch
<gerrit@laosinh.s.bawue.de>:
> On 09/03/2018 10:08 PM, Mia Magnusson wrote:
> > 
> > The A2232 7-port serial card for Amiga uses the 6551 and it seems to
> > think that CTS and DCD is really broken and uses a separate 8520 CIA
> > instead of the 6551's for those signals.
> > 
> > Btw this is probably well known but there is an alternative driver
> > available on Aminet which afaik is a complete rewrite, making that
> > card able to run at 115200 on it's fist two ports with no data loss
> > and almost no cpu load on the Amiga.
> 
> Back then I recommended a hardware hack... Bend then XTAL-Pins of the 
> 8551 or 6551 from the Socket and solder a 3.6864 MHz crystal to it.
> Yes, that was overclocking the chip, but this way you were able to
> get 38400 on one or two ports without any changes to the software.
> You just needed to remember that real baudrate would be double of
> what you selected in the software.

On my A2232, the oscillator were socketed, or maybe I actually
desoldered the original and installed a socket. However I hadn't any
3.6xx crystal but I had one at twice that frequency, and that worked
well for me.

But then I found that driver on Aminet and it worked far better, and I
installed the original crystal instead and used 115200.

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