The present invention facilitates clock and data recovery (330,716/718)
for serial data streams (317,715) by providing a mechanism that can be
employed to maintain a fixed tracking capability of an interpolator based
CDR circuit (300,700) at multiple data rates (e.g., 800). The present
invention further provides a wide data rate range CDR circuit (300,700),
yet uses an interpolator design optimized for a fixed frequency. The
invention employs a rate programmable divider circuit (606,656,706) that
operates over a wide range of clock and data rates (e.g., 800) to provide
various phase correction step sizes (e.g., 800) at a fixed VCO clock
frequency. The divider (606,656,706) and a finite state machine (FSM)
(612,662,712) of the exemplary CDR circuit (600,650,700) are manually
programmed based on the data rate (614,667). Alternately, the data rate
may be detected from a recovered serial data stream (718) during CDR
operations (on-the-fly) utilizing a frequency detection circuit (725) to
automatically program the divider (706) and FSM (712) to provide CDR
circuit operation at the nearest base clock rate (716).