[Coco] DriveWire issues with Coco 1 F/285 Board

Darren A mechacoco at gmail.com
Tue Jul 2 16:43:09 EDT 2013


On Tue, Jul 2, 2013 at 1:02 PM, Torsten Dittel wrote:
>
> I must confess I've never seen the 9600 baud on a scope (I concluded from
> the 10kHz bandwith you mentioned that it would a least reach the
> corresponding voltage levels for each single bit, even if not having a rect
> pulse shape). However, I have seen on a scope what was left at 31250 baud,
> and that's why I can hardly imagine the 57600 baud working flawlessly for
> *any* bit pattern output as Robert was reporting, but who knows how
> "intelligent" modern serial interfaces are, maybe it is sampling the slew at
> very high speed and reconstructing the original data by considering the
> corresponding slew rates.
>

DriveWire for the CoCo 1 operates at 38400 bps because, during
testing, the 57600 bps rate was found to be too fast for the OpAmp.
The 38400 bps rate was found to be reliable with the limited set of PC
serial ports and USB dongles that were tested.  However there may very
well be some hardware that can't handle with the triangular waveforms
at that rate.

Darren



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