For Subclass 1 operation, JESD204B requires that a SYSREF signal is generated.
A periodic SYSREF is valid, but when all of the following conditions are met, the core does not assert TVALID after correctly synchronizing the link:
For a Periodic SYSREF signal, the period must be greater than the Multiframe size in use on the link.
If the SYSREF period must match the LMFC period then setting a non-zero value in RX_BUFFER_DELAY will also fix the problem.
Note It is also a requirement of the JESD204 core that the SYSREF period be a multiple of 4 byte clocks, as the core operates on a 4-byte datapath.
01/07/2014 - Initial release