JESD204B Intel® FPGA IP User Guide

ID 683442
Date 5/05/2023
Public

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4.3.4. Link Reinitialization

The JESD204B TX and RX IP core support link reinitialization.

There are two modes of entry for link reinitialization:

  • Hardware initiated link reinitialization:
    • For TX, the reception of SYNC_N for more than five frames and nine octets triggers link reinitialization.
    • For RX, the loss of code group synchronization, frame alignment and lane alignment errors cause the IP core to assert SYNC_N and request for link reinitialization.
  • Software initiated link reinitialization—both the TX and RX IP core allow software to request for link reinitialization.
    • For TX, the IP core transmits /K/ character and wait for the receiver to assert SYNC_N to indicate that it has entered CS_INIT state.
    • For RX, the IP core asserts SYNC_N to request for link reinitialization.

Hardware initiated link reinitialization can be globally disabled through the csr_link_reinit_disable register for debug purposes.

Hardware initiated link reinitialization can be issued as interrupt depending on the error type and interrupt error enable. If lane misalignment has been detected as a result of a phase change in local timing reference, the software can rely on this interrupt trigger to initiates a LMFC realignment. The realignment process occurs by first resampling SYSREF and then issuing a link reinitialization request.