Reasoning about synchronization in GALS systems

Correct design of interface circuits is crucial for the development of System-on-Chips (SoC) using off-the-shelf IP cores. For correct operation, an interface circuit must meet strict synchronization timing constraints, and also respect sequencing constraints between events dictated by interfacing protocols and rational clock relations. In this paper, we propose a technique for automatically analyzing the interaction between independently specified synchronization constraints and sequencing constraints between events. We show how this analysis can be used to derive delay constraints for correct operation of interface circuits in a GALS system. Our methodology allows an SoC designer to mix and match different interfacing protocols, rational clock relations and synchronization constraints for communication between a pair of modules, and automatically explore their implications on correct interface circuit design.