On Sat, Feb 04, 2006 at 11:55:15PM -0200, Gerhard Fiedler wrote:
> Byron A Jeff wrote:
> 
> >>> I'm not sure I get this yet... What's wrong with using the modem pins
> >>> of a serial port? Or is this what you are thinking of using?
> >> 
> >> That is exactly what he is wishing to do, but part of the discussion
> >> has revolved around how timings are unreliable when using USB-Serial
> >> interfaces.
> > 
> > Bingo.
> 
> Unreliable or slow? 

Both. I know for a fact that some of the Linux USB to serial drivers do
not drive the modem control signals. Also unpredictable timings on the
changing of the signals that do work makes it unreliable.

> What's wrong with a beginner's bootstrap programmer where you can follow
> the individual bits on an LED? :)

It's unnecessary. A couple of one shots gives a perfectly predictable,
repeatable, and reasonably fast interface. There's also enough feedback
to easily calibrate the one shots (or at least verify correct operation).

BAJ
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