In bist (built in self test) how to calculate good known signature pattern which we store in ROM.

 

In bist (built in self test) how to calculate good known signature pattern which we store in ROM.

'bist' or do you mean POST (power-on self test)?

The pattern you store as a signature depends on what you're trying to identify. You need to provide more information, and you can also store it in EEPROM.

 

its BIST (built-in-self-test). we have to calculate the good signature with wich we compare the test pattern output to confirm whether those match or not . if match then there is no fault .

 

You can figure it out from the software if it is well enough documented and you have a lot of spare time but the usual way to generate the BIST "passed" signature is by running the self test on a known good unit. The signature depends wholly on the type and number of tests in the self-test routine. The signature will change if any tests are modified or added.
Regards,
Keith

 

its BIST (built-in-self-test). we have to calculate the good signature with wich we compare the test pattern output to confirm whether those match or not . if match then there is no fault .

AFAIK signatures are not calculated -- they are observed. Why do you think they are calculated?