Using the CRC Generator

When the CRC generator is used, the CRC generator enable must be set and the 64B/66B encoder and 64B/66B decoder must be bypassed.

• CRC_EN should be set to 1'b1.
• DATAPATH_CTRL can only be set to either 2'b01 or 2'b10 depending on whether or not the TX 64B/66B scrambler is bypassed.

Another requirement is that depending on whether or not the TX 64B/66B scrambler is bypassed, the TX CRC generator must be set to provide the expected output endian format. The following must be set:

• When the TX 64B/66B scrambler is bypassed, OUTPUT_BYTE_ORDER must be set to 1'b0.
• When the TX 64B/66B scrambler is enabled, OUTPUT_BYTE_ORDER must be set to 1'b1.