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Observer digieng
Registered: ‎02-26-2016


I would like to use the eFUSE key AES encryption method. Is there a preference in this situation as to whether VCCBATT is tied to VCCAUX or GND. I understand that VCCBATT is for battery backed BRAM but I just wanted to check that this wouldn't be and issue.

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Xilinx Employee
Xilinx Employee
Registered: ‎08-01-2012


VCCBATT is the battery backup supply for the FPGA's internal volatile memory that stores the key for the AES decryptor. For encrypted bitstreams that require the decryptor key from the volatile key memory area, connect this pin to a battery to preserve the key when the FPGA is unpowered. If there is no requirement to use the decryptor key from the volatile key storage area, connect this pin to GND or VCCAUX. The pin name includes the "_0" bank designation but it is not an I/O and not affected by VCCO_0.


In your case you wish to use eFUSE key  instead of the key stored in battery-backed SRAM. So you can connect VCCBATT either to GND or VCCAUX. No issues. 


Please refer http://www.xilinx.com/support/documentation/user_guides/ug470_7Series_Config.pdf for more details about configuration details


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