Good treatise.

I've never known of a UART where the overrun error did NOT halt the
UART hardware. Anybody know of one? Its a serious error.

Jan-Erik Soderholm wrote:
> There are two errors detected, "framing" and "overrun".
>
> A framing error can occure anytime, such as something
> disturbing the serial line. The framing error is cleared
> automaticly whenever there is a correctly "framed"
> character. This is an error out of control by your
> firmware.
>
> The overrun error is different. It *that* occures, you have
> a major application/firmware problem !
> In general, overruns should never occur and one can,
> by design of the firmware, make sure that they don't.
>
>   
>> So what I got a bad character....who cares?
>>     
>
> No, you havn't got "a bad character", your firmware
> didn't read the *previous* characters, which is a bit
> different. And you have no idea what so ever if you
> dropped one, two, three or more characters !
>
> If the framing error flag is set, the *last* received
> char could be corrupted.
> If the overrun flag is set, on *or more* characters
> have been missed and are lost.
>
> So "overrun" is something that should be avoided.
>
>   
<respectful snip>

--Bob
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