Patent ID: 7222213

Claim:
A method of operating a memory system having a memory hub controller coupled to a plurality of memory hubs each of which includes at least one receiver that is initialized before use, the method comprising: transmitting a downstream initialization complete signal from the memory hub controller to one of the memory hubs when initialization of a receiver in the memory hub controller has been completed; determining if a respective downstream initialization complete signal is being received by each of the memory hubs; determining if initialization of at least one receiver in each of the memory hubs has been completed; if the respective downstream initialization complete signal is being received by each of the memory hubs except for a final memory hub furthest downstream from the memory hub controller and initialization of at least one receiver in the memory hub has been completed, transmitting a downstream initialization complete signal from the memory hub; if the respective downstream initialization complete signal is being received by the final memory hub and initialization of at least one receiver in the final memory hub has been completed, transmitting an upstream initialization complete signal from the memory hub; if the respective upstream initialization complete signal is being received by each of the memory hubs determining if an upstream initialization complete signal is being received by the memory hub; if the respective upstream initialization complete signal is being received by each of the memory hubs and initialization of all receivers in the memory hub has been completed, transmitting an upstream initialization complete signal from the memory hub; and if a respective upstream initialization complete signal is being received by the memory hub controller, transitioning the memory system to normal operation.