Edson Brusque wrote:

>   I thought that stopping telling the USART to output a byte would
> maintain it in idle mode, so, with it's output HI (the same as a
> break).  Isn't it?

  No.  A break is a "space" condition (Low on the logic line, positive
voltage on the RS-232) occurring for much longer than two characters.
Idle is as you say, continuous marking.

  The break is used for an "attention" function - something not able to
be communicated as a character.  It can also be seen as a NUL character
continuing beyond the (missing) stop bit.  In fact you generally get a
NUL ($00) detected and passed on before it is realised that it is
actually a break - something to be taken into account.

  Idle OTOH, generates no characters in the receiver.
--
  Cheers,
        Paul B.