EFSM Manipulation to Increase High-Level ATPG Effectiveness

Abstract

The EFSM paradigm can be efficiently adopted to model complex designs without incurring in the state explosion problem typical of the traditional FSM paradigm. However, traversing an EFSM can be more difficult than an FSM because the guards of transitions involve both primary inputs and internal registers. Hard-to-traverse transitions represent a problem when a simulation-based approach is applied to perform functional validation. In fact, they do not allow a complete exploration of the state space. In this paper, EFSM hardto-traverse transitions are classified, and a set of transformations is proposed to generate an EFSM model which is easy to be traversed. This allows pseudo-deterministic ATPGs to more uniformly analyze the state space of the resulting EFSM.

Test Generation Based on CLP

“…Stabilization of EFSMs improves the easiness of traversal (Lee & Yannakakis, 1992), but it can lead to the state space explosion. Thus, in (Di Guglielmo et al, 2006a), a set of theoretically-based automatic transformations has been proposed to generate a particular kind of semi-stabilized EFSM (S 2 EFSM). This particular kind of EFSM allows the ATPG to easily explore the state space of the corresponding DUV reducing the risk of state explosion.…”

Towards Equivalence Checking Between TLM and RTL Models

“…To achieve such a goal, first we need to introduce a formal model that allows us to represent designs at different abstraction levels. Among different alternatives, we select the Extended Finite State Machine (EFSM) [17] since it captures the main characteristics of the state-oriented, activity oriented and structure-oriented model [18].…”

“…Transitions are labeled with an enabling function e, which represents the guard of the transition, and an update function u, which specifies how the values of registers and outputs evolve when the transition is traversed. = {x|((s, x, i), (t, y, o)) ∈ T for y ∈ D} and Y = {y| ((s, x, i), (t, y, o)) ∈ T for x ∈ X}, the enabling and update functions are defined respectively as: [19,17].…”

A methodology for abstracting RTL designs into TL descriptions

“…According to the condition reported in the enabling functions, the EFSM moves from a state to another at each clock cycle executing the HDL code included in the update function of the traversed transition. Note that, an EFSM can be automatically extracted from an HDL description as reported in [13,14].…”

“…In this way, the need of transactors for reusing RTL IPs is removed and a full TL design is obtained. The methodology starts from an extended finite state machine (EFSM) representation of an RTL IP, that can be automatically extracted from the related Hardware Description Language (HDL) code [13,14], and it generates a corresponding abstract model for each of the TLM levels.…”