Mentor v8.6_4 Benutzerhandbuch

FastScan and FlexTest Reference Manual, V8.6_4

Tools Supported: FastScan

Scope: Setup mode

ADD LFsrs lfsr_name {Prpg | Misr} length seed [-Both | -Serial | -Parallel]

[-Out | -In]

Adds Linear Feedback Shift Registers (LFSRs) for use as Pseudo-Random Pattern
Generators (PRPGs) or Multiple Input Signature Registers (MISRs).

The Add LFSRs command defines LFSRs, which FastScan uses as PRPGs, to
create pseudo-random values for the Built-In Self Test (BIST) patterns or as
MISRs to compact responses.

You specify the LFSR’s shift technique by using one of the following shift_type
switches: -Both, -Serial, or -Parallel. You specify the placement of the exclusive-
OR taps by using one of the following tap_type switches: -Out or -In. You can
change the default setting of the shift_type and tap_type switches by using the
Setup LFSRs command.

You use this command primarily for simulating Built-In Self Test (BIST)
circuitry.

•

A required string that specifies the name that you want to assign to the LFSR.

•

A literal that indicates the LFSR functions as a PRPG.

•

A literal that indicates the LFSR functions as a MISR.

•

A required integer, greater than 1, specifying the number of bits in the LFSR.