Nexus: an asynchronous crossbar interconnect for synchronous system-on-chip designs

Asynchronous circuits can provide an elegant and high performance interconnect solution for synchronous systemon-chip (SoC) designs with multiple clock domains. This “globally asynchronous, locally synchronous” (GALS) approach simplifies global timing and synchronization problems, improving performance, reliability, and development time. Fulcrum Microsystems’ SoC interconnect, “Nexus”, includes a 16 port, 36 bit asynchronous crossbar which connects via asynchronous channels to clock domain converters for each synchronous module. Each synchronous module has its own local clock domain, and can send a variable length burst of data to any other module. In TSMC’s LV, Low-K process, the system achieves at with less than area. Power scales linearly with bandwidth, from a few of leakage to at the peak cross-section bandwidth. Latency through the interconnect is plus to clock cycles of the receiving module. This compares favorably with other SoC interconnect solutions that have less bandwidth, higher energy per transfer, and longer latencies. Nexus is an innovative and comprehensive solution to the challenge of SoC interconnect.