[Coco] RS DOS RS232 application?

[Gene Heskett]

On Thursday 14 April 2016 21:02:14 RETRO Innovations wrote:

> On 4/14/2016 7:58 PM, Gene Heskett wrote:
> > On Thursday 14 April 2016 20:34:59 RETRO Innovations wrote:
> >> On 4/14/2016 7:14 PM, Gene Heskett wrote:
> >>> On Thursday 14 April 2016 19:58:35 RETRO Innovations wrote:
> >>>> I would like to test out a mod to my RS232 pak to bring it up to
> >>>> 230kbps.  Is there a simple app around that has source so I can
> >>>> modify it to do 230kbps on my rs232 pak and test?  Or,
> >>>> alternatively, is there a simple terminal that I can run to test
> >>>> out the various existing bps rates?
> >>>>
> >>>>
> >>>> Jim
> >>>
> >>> Unless you have huge buffers, big enough to contain the whole
> >>> transmission, the coco cannot move more than about 90k a second.
> >>
> >> That's fine.  That's approximately 900kbps, far more than I need.
> >>
> >> Any response for my question?
> >>
> >> Jim
> >
> > No, not from a position of authority after having forgotten the
> > kilobaud to kilobyte translation that badly.  I'd fire up the scope
> > and check 2 things, 1 being that the output rise and fall times are
> > no more than 10% of the bit time, and which swing from -7 to +7
> > volts or more, and if the scope is well calibrated, do you see bit
> > times that correspond to 230 kilobaud, a hair over 4.17 u-s per bit?
> >
> > Cheers, Gene Heskett
>
> I'm confident the UART (6551A) will be fine in that area (as I
> regularly use the same circuit on the 65XX side of things, I was
> rather hoping to see it work at a higher level (i.e. an app to show at
> CocoFEST)
>
> Jim
>
I might have some heating concerns in the MC1488-89 dept, particularly if 
they are OEM chips.  I believe they have been silently improved over 
that last 30 some years.
>
> --
> RETRO Innovations, Contemporary Gear for Classic Systems
> www.go4retro.com
> store.go4retro.com


Cheers, Gene Heskett
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