State encoding of large asynchronous controllers

Abstract

A novel method to solve the state encoding problem in Signal Transition Graphs is presented. It is based on the structural theory of Petri nets and can be applied to large specifications with hundreds of signals. This new method opens the door to incorporate logic synthesis in the design flow of large control circuits obtained from high-level specifications. The experimental results validate the quality of the encoded circuits and show the significant improvements that can be obtained by the synthesis of large controllers.

Avoiding irreducible CSC conflicts by internal communication

“…To overcome this drawback we are aiming at the incorporation of speed independent (SI) logic synthesis into a design flow based on syntax-directed translation by resynthesis of the system's control path using STGs; see e.g. [CC06] and [WW07b].…”

“…from Balsa or Tangram with speed-independent logic synthesis from STGs is a promising approach [CC06]. To deal with state-space-explosion, we suggested STG decomposition; a problem is that decomposition can lead to irreducible CSC conflicts.…”

Combining Decomposition and Unfolding for STG Synthesis

“…The second group of benchmarks are newly generated; they are STGs derived from Balsa specifications. These kind of benchmarks was used before by [CC06]. The benchmark SeqParTree(21,10) from there is nearly the same as SeqParTree-05 here; the difference is that we did not hide the internal handshake signals.…”

“…Petrify and Mpsat alone need more than 12 hours (aborted) for either of these benchmarks. In contrast to the decomposition method of [CC03,CC06] we allow components with more than output. This was utilised here: the initial partition was chosen such that each component of the decomposition corresponds to one handshake component.…”

“…(The tool for CSC conflict resolution and decomposition described in [CC06,Car03] was not available from the authors.) In the tables, all times are given as (minutes:)seconds.…”