Device DNAs 57 bits not unique 8/12 parts ordered

[tim_severance]

Hi, I just received hardware where I use XC7K160TFFG676-1 FPGAs and reading the device DNAs I am finding that 8 out of 12 of these FPGAs are not unique for the 57 bits.   Should this not have occurred?   It seems like I have read that the chance of this happening should be near zero.

Thanks.

Tim

[gurupra · Accepted solution]

Hi @tim_severance 

Please check UG470 :

[tim_severance]

@gurupra ,

   Thanks for the response.

   I agree that Xilinx let's us know that it is possible for sure, but the wording that they are "most often unique" would make me think that Xilinx makes some kind of effort to prevent what I am seeing from happening.

   I wasn't expecting this unfortunately and need to look for another method to give each setup a unique ID.

Thanks.

Tim 

[thakurr]

Hi @tim_severance 

We have a full 64 bit FUSE_DNA value unlike before where we had just the 57 bit JTAG DNA value. The added 7 bits of the FUSE_DNA value make it unique to each device. This FUSE_DNA value can be read through JTAG under device properties.