Tech Support > Computer Hardware > Microprocessors > Re: Uart baud rate matching
Re: Uart baud rate matching
Posted by Dave Hansen on August 18th, 2003


On Mon, 18 Aug 2003 17:21:56 +0200, "David Brown"
<david@no.westcontrol.spam.com> wrote:

A 1.36% error combined with a nominal 0% error from the other end
should present you with few problems.

If the other end was potentially 1.36% off in the opposite direction,
You're looking at a combined potential error > 2%, which would make me
nervous.

A 5% error would almost guarantee problems. Consider that about 10
bits are sent to transmit a single byte. Even though everything is
re-synched at the beginning of each byte, the error within a byte
accumulates so that the error at the end of the byte might be 50% or
more of a bit width. Depending how the UART does its bit sampling,
you could end up with an erroneous value for the last bit as much as
50% of the time.

Regards,

-=Dave
--
Change is inevitable, progress is not.

Posted by David Brown on August 19th, 2003



"Richard Henry" <rphenry@home.com> wrote in message
news:3b80b.2348$QT5.954@fed1read02...
That's pretty much what I thought, and what I have seen in practice. Thanks
to all posters for confirming it.

David