Design of Asynchronous Wrappers for High-Concurrency Multi-Point GALS Systems

Abstract

The GALS (Globally Asynchronous, Locally Synchronous) style can be an interesting alternative to complex digital systems that can be based on the “System-on-Chip - SoC” concept. Currently, the major drawback in the design of a GALS system is the asynchronous interface (Asynchronous Wrapper - AW), especially when the GALS system is applied to a multi-point topology with high concurrency communication. The AW interfaces found in literature are usually based on controller ports. They are responsible for data communication between locally synchronous modules, where, for each point of data communication, there is an input or output port. For multi-point topologies there may be an excessive number of ports, where the number of ports leads to complex AWs mainly when there is concurrent communication which brings a high increase in area. This paper proposes a new asynchronous GALS interface focused on multi-point GALS of high concurrency. Considering a multi-point data communication system, the proposed AWs achieved an average reduction in area (LUTs + FFs) that corresponds to additional circuits of 177%, when compared to AWs found in literature.