Occasional Contributor
ContributorHi
In your non-working case, sysref is 3.90625MHz.
Few things you can check:
1) Sysref input must be provided to the JESD204B system. If have multiple links, each link will receive SYSREF pulse and initialize at the same time.
Page 63 of JESD204B User Guide-01142 stated that
"...The IP core also ensures that at least one SYSREF rising edge is sampled before deasserting SYNC_N."
It means the SYSREF should be sent out few cycle before the SYNC_N (dev_sync_n) of the RX IP core can be deasserted.
There must be at least one SYSREF pulse detected before the dev_sync_n will goes high.
The dev_sync_n will never goes high if there are no SYSREF pulse detected at all.
You may refer to Figure 14 for the SYSREF & SYNC_N waveform.
2) The dev_sync_n will never goes high if no SYSREF pulse is detected at all, it means the core will not come out of reset.
The SYSREF pulse should be issued while the core is in reset.
If the core misses the one SYSREF pulse that is sent, the core will remains in reset.
