Source synchronous bus signal alignment compensation mechanism

An apparatus that compensates for misalignment on a synchronous data bus, the apparatus comprising:

• a microprocessor, comprising:
• a replica distribution network, configured to receive a first signal, and configured to generate a second signal, wherein said replica distribution network comprises replicated propagation lengths, loads, and buffering of a radial distribution network for a strobe, and wherein said radial distribution network equalizes all propagation paths for said strobe as it is distributed;
• and
• a bit lag control element, configured to measure a propagation time beginning with assertion of a first signal and ending with assertion of a second signal, wherein a radial distribution element generates said second signal as a delayed version of said first signal, said delayed version corresponding to a portion of a radial propagation path for a data strobe, and configured to generate a first value on a lag bus that indicates an adjusted propagation time, said bit lag control element comprising:
• delay lock control, configured to select one of a plurality of successively delayed versions of said first signal that coincides with said assertion said second signal, and configured to generate a second value on a lag select bus that indicates said propagation time;
• adjust logic, coupled to a circuit and to said lag select bus, configured adjust said second value by an amount prescribed by said circuit to yield a third value that is output to an adjusted lag bus;
• and
• a gray encoder, configured to gray encode said third value to generate said first value on said lag bus.

A method that compensates for misalignment on a synchronous data bus, the method comprising:

• via a replica distribution network, receiving a first signal, and generating a second signal, wherein the replica distribution network comprises replicated propagation lengths, loads, and buffering of a radial distribution network for a strobe, and wherein the radial distribution network equalizes all propagation paths for the strobe as it is distributed;
• measuring a propagation time beginning with assertion of a first signal and ending with assertion of a second signal, said measuring comprising:
• selecting one of a plurality of successively delayed versions of the first signal that coincides with assertion of the second signal;
• adjusting the propagation time by an amount prescribed by a circuit to yield an adjusted propagation time;
• and
• gray encoding the adjusted propagation time to generate a value on a lag bus.