I am following the power up sequence exactly, waiting 500mS, clearing my Rx buffer, sending 'U' then looking for ACK. Sometimes all is fine, but at others I do not get ACK nor NACK, but a random char (due to the baud rate not being set). I then send another 'U' and repeat. Again, sometimes all is OK and I can proceed. Then, whilst running, if the serial link was to be interrupted or noisy(?) the Picasso would miss a character and get out of sync and so I would not get an ACK back when expected and so I would hang waiting for it. Is there a way of 'flushing' out the current Picasso command so that I can resend it afresh, other than dropping the Reset line, which would clear the screen, which I do not want to do.