Recalibration of source synchronous systems

A source-synchronous receiver, comprising:

• a first receiver configured to receive a strobe, the first receiver including a strobe delay circuit;
• second receivers configured to receive data signals referenced to the strobe, the second receivers including data delay circuits;
• and
• a calibration circuit configured to:
• perform initial calibration to determine an initial strobe delay for the strobe delay circuit and initial data delays for the data delay circuits;
• measure first data eye margins of the data signals at a first time;
• calculate metrics for the data signals based on the first data eye margins;
• measure second data eye margins of the data signals at a second time;
• and
• update the data delay circuits and the strobe delay circuit based on the second data eye margins and the metrics.

A system, comprising:

• a source-synchronous transmitter coupled to a source-synchronous receiver through a plurality of transmission lines, the source-synchronous receiver comprising a first receiver configured to receive a strobe, the first receiver including a strobe delay circuit, second receivers configured to receive data signals referenced to the strobe, the second receivers including data delay circuits, and a calibration circuit configured to:
• perform initial calibration to determine an initial strobe delay for the strobe delay circuit and initial data delays for the data delay circuits;
• measure first data eye margins of the data signals at a first time;
• calculate metrics for the data signals based on the first data eye margins;
• measure second data eye margins of the data signals at a second time;
• and
• update the data delay circuits and the strobe delay circuit based on the second data eye margins and the metrics.