>>USB requires better clock accuracy than you are likely to get without a
>>resonator or crystal.
>
> That's what I've always thought as well.  But don't recent FDTI USB
> chips work without an external crystal?
>
> How do they work their magic?
>
> Thanks!
>
> dwayne

I think they might adjust their timing based on the clock rate of the signa=
l=20
from the host. I have used that trick to do bit-banged RS232 async without =
a=20
crystal.

-- Bob Ammerman
RAm Systems

--=20
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