Design Of An Improved And Robust Asynchronous Wrapper (Aw) For FPGA Applications

  • Duarte L. Oliveira
  • Lester A. Faria
  • Eduardo Lussari
Keywords: asynchronous logic, essential hazard, FPGA, interface, finite state machine, XBM specification


Contemporary digital systems must be based on the “System-on-Chip – SoC” concept. An interesting style for SoC design is the GALS paradigm (Globally Asynchronous, Locally Synchronous), which can be used to implement circuits in FPGAs (Field Programmable Gate Arrays). However the implementation of asynchronous interfaces (asynchronous wrapper – AW) constitutes a major drawback for this kind of devices. Although there is a typical AW design style, which is based on asynchronous controllers providing communication between modules (called ports), port controllers are subject to essentialhazard when implemented in FPGAs. In this context, this paper proposes a new asynchronous GALS wrapper architecture, suitable for implementations in any kind of FPGAs. The proposed port controllers showed to be essential-hazard-free, not needing any special cares in implementation concerning to LUTs choice. Additional advantages of the proposed architecture are: total autonomy that synchronous modules achieve when interacting with the asynchronous wrapper; the ports can be synthesized in the direct mapping style (so without knowledge of asynchronous logic synthesis); and the ports interact with environment in Ib/Ob Mode, not needing a timing analysis. Simulation results show the applicability of the proposed architecture and lead to its practical implementations in FPGAs.