US Patent 7839966 Asynchronous data sampling using CDR receivers in lock-to-reference mode

Sampling and analysis of input data is implemented within the programmable logic resource without using external equipment. CDR circuitry can be set to reference clock mode. In this mode, a reference clock signal is multiplied by a factor to generate a sample rate. The sample rate is divided by another factor, the desired width of the sampled data, to generate an output clock. The input data is sampled at the sample rate and sent to core circuitry based on the output clock. Dedicated circuitry in the core circuitry is configured to perform analysis on the sampled data.