The Post CRC (POST_CRC) constraint enables or disables the Cyclic Redundancy Check (CRC) error detection feature for configuration logic, allowing for notification of any possible change to the configuration memory. This feature is only supported in 7 series FPGAs. For more information refer to the 7 Series FPGAs Configuration User Guide (UG470) [Ref 1].
TIP: Alternatively, Xilinx recommends use of the Xilinx Soft Error Mitigation (SEM) IP for all architectures. This IP automates the implementation of single event upset (SEU) detection and correction. For additional information, refer to the Soft Error Mitigation Controller LogiCORE IP Product Guide (PG036) [Ref 28].
Enabling the POST_CRC property controls the generation of a pre-computed CRC value in the bitstream. As the configuration data frames are loaded, the device calculates a Cyclic Redundancy Check (CRC) value from the configuration data packets. After the configuration data frames are loaded, the configuration bitstream can issue a Check CRC instruction to the device, followed by the pre-computed CRC value. If the CRC value calculated by the device does not match the expected CRC value in the bitstream, the device pulls INIT_B Low and aborts configuration.
When CRC is disabled a constant value is inserted in the bitstream in place of the CRC, and the device does not calculate a CRC.
Architecture Support
7 series FPGAs.
Applicable Objects
•Design (current_design)
°The current implemented design.
Values
•DISABLE: Disables the Post CRC checking feature (default).
•ENABLE: Enables the Post CRC checking feature.
Syntax
Verilog and VHDL Syntax
Not applicable
XDC Syntax
set_property POST_CRC ENABLE | DISABLE [current_design]
XDC Syntax Example
set_property POST_CRC Enable [current_design]
Affected Steps
•Write Bitstream
•launch_runs
See Also