Mentor v8.6_4 manual Add Pin Constraints, ADD PIn Constraints primaryinputpin... constraintformat

Command Dictionary Add Pin Constraints

Add Pin Constraints

Tools Supported: FastScan and FlexTest

Scope: Setup mode

Usage

ADD PIn Constraints primary_input_pin... constraint_format

Description

Adds pin constraints to primary inputs and input channel to I/O pins.

The Add Pin Constraints command performs slightly differently depending on whether you use FastScan or FlexTest. The following paragraphs describe how the command operates for each tool.

FastScan Specifics

The Add Pin Constraints command restricts the chosen pins to a specific value during the ATPG process.

For every regular primary input for which you do not specify a constraint by using the Add Pin Constraints command, saving patterns will automatically default to the NR constraint format except where the CRO and CR1 formats are used.

The NR constraint format is not available from the FastScan command line interface.

Note

You can constrain a clock pin to its off-state to prevent its use as a capture clock during the ATPG process. The constrained value must be the same as the clock off-state or an error occurs. You may wish to use a return format if the pin utilizes clock timing in the test_setup procedure (this is an AVI requirement).

You can also constrain a scan-in pin. You cannot constrain an equivalent pin, with the exception of a simple equivalent pin. If you constrain a primary input to be a constant Z, but it does not connect to a tri-state net, FastScan converts the pin value to a constant X; FastScan also displays a warning message indicating that it performed the conversion.

FastScan and FlexTest Reference Manual, V8.6_4 2-93