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AR# 45329

HMAC error - Cannot download bit file after programming eFUSE register


I have programmed the eFUSE register, however, the bit file cannot be downloaded successfully.
It shows a HMAC error in the BOOTSTS register.

Data stored in the eFUSE register is confirmed as being the same data as expected.


A HMAC error can be seen if the '-g StartUpClk:CClk' option is used when generating the bit file.
When programming with iMPACT, the bitstream startup clock will be changed from a CCLK to a JTAG clock.

The bitstream stored in PC memory will be modified, resulting in a HMAC error.

To work around this, disable Startup clock Auto Correction in iMPACT.

You can do this in Edit -> Preferences. 

This problem does not arise when programming FPGA through configuration data stored in external Flash memory.

AR# 45329
Date Created 12/07/2011
Last Updated 01/30/2015
Status Active
Type General Article
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