> If you look at the timing diagram in the data sheet, the TRMT
> bit gets set at the beginning of the stop bit. You should
> wait one bit time extra before disabling any buffers or letting
> another unit start transmitting.

Most of the time you don't have to wait for the stop bit to complete
because the line will be high anyway.  In the RS-485 case I mentioned,
there is no problem reversing your bus interface before the stop bit is
complete.  The receiver will see the line high but just interpret it as
idle bus.  Since the stop bit is at the bus undriven level, the bus will
signal the stop bit whether you stop driving it part way thru or not.  All
other receivers will wait to the end of the stop bit time before
transmitting anything new.  In fact, reversing your bus tranceiver from
send to receive immediately after the start of the stop is the *best* time
to do it because you've got the whole stop bit during which the next bus
sender won't be sending.

In the power down case I mentioned, it again makes sense to power down as
soon as possible after the start of the stop bit.  During power down, the
TX line will be driven high indefinitely.


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