A layered approach to behavioral modeling of bus protocols

This paper presents a hierarchical approach to designing behavioral functional models (BFMs) for bus protocols, based on the protocols' defined hierarchies of data-transfer. Classical approaches to BFM design for bus protocols restrict themselves to the most rudimentary levels of data-exchange, leading to inefficient and error-prone modeling of higher level data transfers. This paper presents a layered approach to BFM design, in which each level of data transfer is controlled or monitored by a separate layer of BFM functions. This approach addresses all levels of data-transfer abstractions, and increases the scope for reuse across multiple projects. We present a case-study of the successful application of this methodology in the implementation of Synopsys' DesignWare/sup TM/ USB (Universal Serial Bus) Functional Model (UBFM).