Patent ID: 7813381

Claim:
A method for data rate detection using an automatic rate detection system embodied in first integrated circuit to detect a data rate of a data stream processed by a clock and data recovery circuit embodied in second integrated circuit, comprising the steps of: re-clocking the data stream with the clock and data recovery circuit; maintaining at least one status flag with the clock and data recovery circuit; communicating the state of the at least one status flag from the clock and data recovery circuit in the second integrated circuit to the automatic rate detection system in the first integrated circuit; determining a data rate of the data stream with the automatic rate detection system upon identifying a transition in a data rate of the data stream based upon the state of the at least one status flag; indicating whether a change in the transition density of the data stream is detected with the at least one status flag; and determining when a change in the transition density of the data stream as indicated by the state of the status flag is due to an actual change in the data rate of the data stream by: maintaining a count of a number of occurrences of a high state of the status flag; and determining the data rate of the data stream if the count is at least as great as a predefined threshold.