A high speed, two-way serial interface with a scrambler and de-scrambler
may be tested by sending a single word repeatedly through the scrambler
to create a pseudo-random sequence. The pseudo-random sequence is then
passed through the transmitter and looped back through the receiver of
the serial interface. The pseudo-random sequence is then descrambled and
compared to the input word. Since the input sequence is only a single
word rather than a series of words, the comparison is very simple and
capable of being performed within the serial interface itself without the
need for external test equipment.