editor's blog
Subscribe Now

Describing User-Defined Faults

In today’s article on cell-aware fault modeling, we described how specific layout-dependent faults can be accounted for in the test suite, increasing the test coverage beyond what stuck-at modeling provides and yet keeping the vector count down below what gate-exhaustive modeling would require.

But there has to be some way of defining these specific “user-defined” faults so that the test generation program can include them in the test suite.

Mentor devised their so-called “User-Defined Fault Model”, or UDFM, language to handle this. It’s a human-readable and -writable format, and you can use it to define both static and transition faults. This allows you to describe specific custom faults manually if you wish, although, as described in the article, it would be written out automatically by the tools.

As an example, the following would define the four possible alternative tests for the static fault caused by the low-resistance bridge example in the article:

Fault “Bridge-R4” {

       Test {StaticFault “Z”=0; Condition “S0”=0,”S1”=0,”D0”=0,”D1”=-,”D2”=1}

       Test {StaticFault “Z”=0; Condition “S0”=1,”S1”=0,”D0”=-,”D1”=0,”D2”=1}

       Test {StaticFault “Z”=0; Condition “S0”=0,”S1”=1,”D0”=1,”D1”=-,”D2”=0}

       Test {StaticFault “Z”=0; Condition “S0”=1,”S1”=1,”D0”=-,”D1”=1,”D2”=0}

}

Leave a Reply

featured blogs
May 18, 2018
https://youtu.be/O1r7cqyVm90 I was on China24 on CGTNAmerica earlier this week, being interviewed about the Chinese Semiconductor Industry. www.breakfastbytes.com Sign up for Sunday Brunch, the weekly Breakfast Bytes email....
May 17, 2018
Just about everybody wishes they had more time to pursue a hobby or a side project.  Some aspire to be painters or furniture makers.  Others like to rebuild cars.  Even others enjoy electronics in any form. The Maker Movement attracts and caters to tinkerers, hobbyists, st...