A method and apparatus for evaluating and optimizing a signaling system is
described. A pattern of test information is generated in a transmit
circuit of the system and is transmitted to a receive circuit. A similar
pattern of information is generated in the receive circuit and used as a
reference. The receive circuit compares the patterns. Any differences
between the patterns are observable. In one embodiment, a linear feedback
shift register (LFSR) is implemented to produce patterns. An embodiment
of the present disclosure may be practiced with various types of
signaling systems, including those with single-ended signals and those
with differential signals. An embodiment of the present disclosure may be
applied to systems communicating a single bit of information on a single
conductor at a given time and to systems communicating multiple bits of
information on a single conductor simultaneously.