Ascent now automatically ensures X-robust designs

Explicit and implicit X sources (X assignments in RTL and non-resettable flops, respectively) in the designs can lead to many challenging issues for design verification, such as masking real design errors and causing RTL-to-netlist simulation mismatches.

Depending on coding styles, simulation results can be X-pessimistic, which lead to unnecessary unknown values; or X-optimistic, which result in known values when they should have been unknown.

Design and verification teams write properties to trap Xs or instrument two-value simulation with random initialisation to avoid X ambiguity in order to detect design errors.

However, these approaches take a considerable amount of manual and computational resources without offering the complete confidence of X robustness.

Ascent PBV offers a multi-faceted solution that addresses the problem through structural and formal analysis, as well as by augmenting simulation using Ascent Simportal.

Explicit and implicit X sources are automatically detected.

Formal techniques are used to prove X-optimism safe designs.

Ascent Simportal can augment simulation to detect X-excitation, control X-pessimism and eliminate X-optimism without loss of efficiency.

It is an automatic and comprehensive solution that detects and debugs design errors and RTL/netlist simulation mismatches.