On 19/05/2011 13:25, Olin Lathrop wrote:
> Michael Watterson wrote:
>> >  The accuracy of internal oscillator is such that if the other end is
>> >  near the edge of allowable timing error, it may not work.
>> >  I think about 2400 is maximum safe speed without a crystal. Maybe
>> >  less.
> This is a common fallacy.  The absolute baud rate doesn't matter.  Using =
a
> slower baud rate doesn't help since its the relative error between sender
> and receiver that matters.  1/4 bit time after 8.5 bits is the same
> percentage whether at 115.2 Kbaud or 2400 baud.
>

Actually of course you are right. I was thinking of Software bit banged=20
serial on windows. Unless you write a device driver or bypass OS you=20
can't get stable timing for each bit. Thus the speed does matter.

--=20
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