uart.flush()
flush() will wait until all characters but the last one have been sent.
It returns while the last character is sent. If needed, the calling
code has to add one character wait time. To avoid a permanent lock,
a timeout applies depending on the size of the FIFO and the baud rate.
ret = uart.txdone()
ret is True if no transfer is in progress. It returns already True when
the last byte of a transfer is sent.
ret is False otherwise.
Note: the uncrustify configuration is explicitly set to 'add' instead of
'force' in order not to alter the comments which use extra spaces after //
as a means of indenting text for clarity.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
