Data bus using synchronous fixed latency loop including read address and data busses and write address and data busses

摘要

Data transfer between a master node (300) and plural memory nodes (301-308) follows a synchronous fixed latency loop bus (255). Each memory node includes bus interface (311-318) which passes command, write data, write address, and read data and read address to a next memory node in the loop. Each memory node performs a read from its memory at the specified address if a read command is directed to it. Each memory node performs a write to its memory at the specified address if a write command is directed to it. Simultaneously read and write to a single node is prohibited. This configuration provides a fixed latency between the issue of a read command and the return of the read data no matter which memory node is accessed. This configuration prevents collision of returning read data and of incoming write data. This configuration provides fixed loading to each stage regardless of the number of memory nodes. Thus the design of large systems operating at high speeds is simplified.