Cyclone V - CRC_ERROR Automatic Reconfiguration

Hi,

We have developed a board with a Cyclone V FPGA and we want to implement automatic reconfiguration in case a CRC_ERROR is detected in user mode.

For example, if a SEU alters FPGA configuration data.

In our prototype, we connected the CRC_ERROR pin to an inverting buffer, and the output of the buffer to nCONFIG.

According to the FPGA documentation, CRC_ERROR goes high when a CRC error is detected, then nCONFIG goes low, an automatic reconfiguration is achieved.

However, our implementation causes an error during FPGA configuration. When we try to program the FPGA, the programmer gives an error.

Disconnecting nCONFIG from CRC_ERROR inverter, solves the error, and the FPGA is configured correctly.

When the FPGA is "empty", CRC_ERROR is high by default, maybe if nCONFIG is low during the configuration process, it is interpreted as an error.

Can you help us about how to implement automatic reconfiguration when CRC_ERROR is detected?