Heterogeneous Simulation - Mixing Discrete-Event Models with Dataflow
W.-T. Chang, S. Ha and E. A. Lee
Invited paper, RASSP special issue, J. of VLSI Signal Processing, to appear, 1996
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ABSTRACT
This paper relates to system-level design of signal processing systems, which are often heterogeneous in
implementation technologies and design styles. The heterogeneous approach, by combining small,
specialized models of computation, achieves generality and also lends itself to automatic synthesis and
formal verification. Key to the heterogeneous approach is to define interaction semantics that resolve the
ambiguities when different models of computation are brought together. For this purpose, we intro duce a
tagged signal model as a formal framework within which the models of computation can be precisely
described and unambiguously differentiated, and their interactions can be understood. In this paper, we will
focus on the interaction between dataflow models, which have partially ordered events, and discrete-event
models, with their notion of time that usually defines a total order of events. A vari ety of interaction
semantics, mainly in handling the different notions of time in the two models, are explored to illustrate the
subtleties involved. An implementation based on the Ptolemy system from U.C. Berkeley is described and
critiqued.
Send comments to Edward A. Lee at eal at eecs berkeley edu .
