When using the SPI-4.2 Core targeting Virtex-4 (v7.0, v7.1. v7.2, v7.3), I receive a false SnkFFBurstErr. Additionally, prior to SnkFFBurstErr assertion, the following four signals might all be asserted at the same time for one to two clock cycles:
This issue is dependent on burst size, data traffic pattern, and user clock frequency and phase relationship. Although this issue might not surface in functional simulation, it can occur in hardware and must be addressed by installing a patch.
This problem is fixed in the SPI4.2 v7.3 patch.
For more information, see (Xilinx Answer 22238).