Meeting setup/hold times for a repetitive signal relative to a clock

摘要

Clock generation for capturing a repetitive signal relative to a clock includes clock circuitry to provide a clock with active and inactive clock edges within a clock period, and signal capture circuitry to capture repetitive signal transitions at an active clock edge, based on pre-defined setup and hold times which determine a setup/hold window. Clock phase adjustment circuitry is configured to adjust clock phase so that the repetitive signal transitions occur within a signal capture window between setup/hold windows. Clock phase adjustment can be based on: aligning the clock inactive edges to the repetitive signal transitions; and/or averaging successive phase comparisons of the clock and the repetitive signal transitions; and/or selectively performing an initial polarity inversion to generate a polarity inverted clock, and then adjusting clock phase of the polarity inverted clock. An example implementation is JESD204B (subclass1) to adjust DEVCLK phase relative to a SYSREF timing reference control signal.