Patent ID: 7062688

Claim:
A communication system, comprising: a first link, wherein the first link comprises a first data line arranged to transmit a first data signal and a first clock line arranged to transmit a first clock signal; a first latch device arranged to latch the first data signal; and a first test circuit operatively connected to the first link, wherein the first test circuit is arranged to test the first link, the first test circuit comprising: a first adjustment circuit arranged to generate a first adjustable clock signal based on the first clock signal, wherein the first adjustment circuit is arranged to adjust a timing of the first adjustable clock signal relative to the first data signal when the first link is tested, and wherein the first latch device is responsive to the first adjustable clock signal, and a first pattern comparator arranged to compare a first latched test pattern signal to a first test pattern signal, wherein the first latch device is arranged to latch the first test pattern signal from the first data line to generate the first latched test pattern signal; and a counter, wherein the first link is periodically testable by the first test circuit based on the counter.