Mentor v8.6_4 User Manual

FastScan and FlexTest Reference Manual, V8.6_4

Tools Supported: FlexTest

Scope: All modes

SET FAult Sampling percentage [-Seed integer]

Specifies the fault sampling percentage.

The Set Fault Sampling command specifies the fault sampling percentage that
FlexTest uses for circuit evaluation. The default upon invocation of the tool is to
process all faults (100%).

Fault sampling allows you to process a fraction of the total faults and thus
decrease process time when you need to evaluate a large circuit. Once you specify
a percentage, the tool randomly picks the fault samples to process.

•

A required positive integer from 1 to 100 that specifies the fault sampling
percentage that you want FlexTest to use for circuit evaluation. The invocation
default is 100 percent.

•

-Seed integer

Specifies a seed to be used in the selection of fault sampling. Specifying
unique seed values for different runs can give more accurate results when
using fault sampling. The integer must be in lower case 32-bit hex
representation. The initial default is 0xcccccccc. Since the random number
generator is implemented by a linear feedback shift register, 0 is not a possible
value for integer. If the -Seed option is not used, the previously specified seed
will be used.

The following example performs an ATPG run using a fault sampling of 50
percent of the total faults: