1.1.1.5 Eye Monitor

The eye monitor is on-device circuitry to visualize the post-equalization signal quality in the receive path while the data path is still active in the system. The non-destructive eye monitor runs a separate sampler in parallel with the CDR and DFE data sampler. This permits the system to remain operational while the eye monitor is functioning.

The eye monitor systematically adjusts the offsets across the complete eye, calculates the bit-error rate (BER) for each offset setting, then correlates the BER and offset to statistically rebuild the eye diagram. Eye diagram statistics can be read and reconstructed using the Libero SmartDebug tools, which permits access through a JTAG interface for transceiver debugging and test access. For more information, see Eye Monitoring.