A Bundled-Data Asynchronous Circuit Synthesis Flow Using a Commercial EDA Framework

Contemporary silicon technology enables integrating billions of transistors and allows the creation of complex systems-on-chip. At the same time, strict power dissipation budgets and growing interest in high performance battery-powered devices drive the need for energy-efficient high performance circuits. Bundled-data asynchronous circuits are good candidates for high performance low power systems, as they operate with average-case delays and present reduced switching activity when compared to other asynchronous templates. The correct operation of bundled-data circuits relies on constraints that describe the timing relationships between data and control signals. However, commercial EDA frameworks do not offer an encompassing support to ensure the closure of such constraints, making implementation challenging. This paper proposes a synthesis flow to enable the description and enforcement of relative timing constraints at both logic and physical synthesis levels, using the Synopsys framework and a set of in-house scripts. Two case studies illustrate the flow: a pipelined multiplier and a network on chip input buffer FIFO, the latter comprising a non-linear pipeline and complex control circuits. Both case studies target the STMicroelectronics 28nm FDSOI technology, and validation occurs with post-layout simulations. Overall, the flow provides an automatic approach to meet relative timing constraints in a template-agnostic manner for bundled-data circuits design.