Mentor v8.6_4 manual Compress Patterns, Compresses patterns in the current test pattern set

Command Dictionary Compress Patterns

Compress Patterns

Tools Supported: FastScan and FlexTest

Scope: Atpg mode

Usage

For FastScan

COMpress PAtterns [passes_integer] [-Reset_au] [-MAx_useless_passes integer] [-MIn_elim_per_pass number]

For FlexTest

COMpress PAtterns [passes_integer] [-Force] [-MAx_useless_passes integer] [-MIn_elim_per_pass number]

Description

Compresses patterns in the current test pattern set.

The Compress Patterns command performs static pattern compression on the current test pattern set by repeating fault simulation for the patterns in either reverse or random order and selecting only those patterns required for detection. The passes_integer argument specifies the number of pattern compression passes. The first pattern compression pass runs in reverse order and then alternates between random and reverse for additional passes. If you do not specify a passes_integer argument, the tool performs only a single compression pass.

FastScan Specifics

If you specify the -Reset_au option, then when FastScan performs pattern compression, it selects the AU faults for later fault simulation. If during pattern compression these AU faults simulate as possible-detected, the tool labels them as PU (possible-detected—ATPG_untestable) and they receive test coverage credit as possible-detected faults. If the number of pattern compression passes is greater than one, FastScan only performs the resetting of the AU faults for the first pass.

The Compress Patterns command has a residual memory effect. The initial mode (reverse/random) is not fixed. Instead, it toggles back and forth, starting with the mode last used in the same run. FastScan always starts with the reverse order at invocation.

FastScan and FlexTest Reference Manual, V8.6_4 2-149