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AR# 25002

Spartan-3A Family - How do I determine the Post-Configuration CRC calculation time?


How is the Post-Configuration CRC run time calculated for the Spartan-3A?


The Post-Configuration CRC checking engine continuously runs in the device as long as there is a clock source clocking the CRC logic.

The device shifts out one bit from the configuration logic per clock period; this is shifted into the CRC checking function consisting of a shift register.

You can calculate the total run time for one CRC check by multiplying the total number of configuration bits by the clock period.


- XC3S50A has 437,312 bits running at 12 MHz; will take 0.0364 seconds

- XC3S1400A has 4.755,296 bits running at 12 MHz; will take 0.39627 seconds

AR# 25002
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article