Visible to Intel only — GUID: nik1411442190566
Ixiasoft
Visible to Intel only — GUID: nik1411442190566
Ixiasoft
3.20.2. CPRI IP Self-Synchronization Feature
Altera® provides a self-synchronization testing feature that supports an RE target in a CPRI link external loopback configuration. This feature is intended to work correctly only for Layer 1 testing.
By default, only an REC host can function correctly in a CPRI link external loopback configuration. An RE target in external loopback configuration cannot achieve frame synchronization, because the CPRI RX interface must lock on to the K28.5 character before the CPRI TX interface can begin sending K28.5 characters. Therefore, no K28.5 character is ever transmitted on the RE target loopback CPRI link.
However, in an RE target CPRI IP you can specify that the CPRI TX interface begin sending K28.5 characters before the CPRI Rx interface locks on to the K28.5 character from the CPRI link. This feature supports a CPRI RE target in achieving frame synchronization without being connected to a CPRI host, and allows you to test your CPRI RE target without the need for an additional CPRI IP.
To turn on this feature, connect your CPRI RE target in a CPRI link external loopback configuration, and set the tx_enable_force field of the L1_CONFIG register to the value of 1.