Write leveling of memory units designed to receive access requests in a sequential chained topology

A memory controller provided according to an aspect of the present invention uses a slower clock signal during write leveling compared to when performing write operations thereafter. Due to such use of a slower clock signal, the various desired delays can be determined accurately and/or easily. In an embodiment, the frequency of the slower clock signal is determined based on the maximum fly-by delay (generally the delay between sending of a signal on the shared sequential path and the receipt at the memory unit in the sequence) that may be present in the memory system. For example, if the fly by delay can be M (an integer) times the time period of the clock signal during normal write operations, the slower clock signal may have a time period of M times that of the clock signal during write operation.