In UltraScale+ devices supporting the 100G Ethernet RS-FEC Hard block, a Hard FEC Wrapper IP option can be selected using a fixed line rate of either 24,330.24, 12,165.12, 10,137.6, or 8,110.08 Mb/s. This allows the CPRI IP to be converted into a four lane CPRI Hard RS-FEC Receiver IP.
All four CPRI lanes must run at the same line rate. Line speed negotiation is not currently supported in Hard FEC Wrapper IP implementations.
This option is for advanced use cases only with bespoke modified CPRI IP or with customer-specific CPRI IP.
Xilinx recommends instead, using up to three CPRI IP cores with shared logic in the example design and one with shared logic in the core, so that it can share its Hard FEC with the other three CPRI cores. The CPRI IP core is designed to share its 100G Hard FEC between four CPRI lanes in this way.