A method and apparatus for signaling between devices of a memory system is
provided. In accordance with an embodiment of the invention, one or more
of several capabilities are implemented to provide heretofore
unattainable levels of important system metrics, for example, high
performance and/or low cost. These capabilities relate to timing
adjustment capabilities, bit time adjustment capabilities, cycle time
selection, use of differential and/or non-differential signaling for bus
signals and/or clock signals, use of termination structures on a bus,
including integrated termination structures, and active control circuitry
to allow adjustment to different characteristic bus impedances and
power-state control, including a calibration process to optimize the
termination value, use of slew rate control circuitry and transfer
characteristic control circuitry in the predriver and driver of
transmitter blocks to allow adjustment to different characteristic bus
impedances and to allow adjustment for other bus properties, including a
calibration process to optimize the such circuitry, and/or provision of a
memory component designed to prefetch (preaccess) words that are wider
than the width of the data bus so that the memory access bandwidth
approximately matches the transfer bandwidth, and memory component able
to adjust the size of the prefetch (preaccess) word to accommodate
connection to data buses of different width.