[Coco] DW and 6551

[Aaron Wolfe]

On Feb 10, 2015 11:36 PM, "Darren A" <mechacoco at gmail.com> wrote:
>
> On Tue, Feb 10, 2015 at 8:52 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:
>
> > In theory a UART would be a lot more efficient than the bitbanger.
> > However, in reality, Darren's awesome bitbanger routines are so much
faster
> > than the 6551 can go that it doesn't work out that way in this
particular
> > situation.
> >
>
>
> Actually the 6551 can do 115 kbps.  All you have to do is configure the
> baud rate generator to use the External Clock setting. This will cause the
> bit rate to be equal to 1/16 the crystal frequency.  The RS-232 Pak has a
> 1.8432 MHz crystal (1,843,200 / 16 = 115,200).
>
> The only real question is whether or not the level shifting circuitry in
> the Tandy pak can operate at that speed.
>

Maybe the level shifters are the bit I can't remember.  I had some
conversations with people who generally know the coco inside and out, and
walked away with the understanding that high speed on the deluxe pak was a
no go, because of (something) and not really the 6551 itself.  But that was
years back.