50G Interlaken MegaCore Function User Guide

ID 683217
Date 9/20/2022
Public

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4.4. Interleaved and Packet Modes

You can configure the 50G Interlaken IP core to accept interleaved data transfers from the application on the TX user data transfer interface, or to not accept interleaved data transfers on this interface. If the IP core can accept interleaved data transfers, it is in Interleaved mode, sometimes also called Segmented mode. If the IP core does not accept interleaved data transfers, it is in Packet mode. The value you specify for the Transfer mode selection parameter in the 50G Interlaken parameter editor determines the IP core transmit mode.

In Packet mode, the 50G Interlaken IP Core performs Optional Scheduling Enhancement based on Section 5.3.2.1.1 of the Interlaken Protocol Specification, Revision 1.2. The IP core ignores the itx_sob and itx_eob signals. Instead, the IP core performs optional enhanced scheduling based on the settings of BurstMax, BurstMin, and BurstShort.

In Interleaved mode, the 50G Interlaken IP Core inserts burst control words on the Interlaken link based on the itx_sob and itx_eob inputs. The internal optional enhanced scheduling is disabled and the BurstMax and BurstMin values are ignored. BurstShort is still in effect. To avoid overflowing the transmit FIFO, you should not send a burst that is longer than 1024 bytes.

In Interleaved mode or in Packet mode, the 50G Interlaken IP core is capable of accepting non-interleaved data on the TX user data transfer interface (itx_din_words). However, if the IP core is in Interleaved mode, the application must drive the itx_sob and itx_eob inputs correctly.

In Interleaved mode or in Packet mode, the 50G Interlaken IP core can generate interleaved data transfers on the RX user data transfer interface (irx_dout_words). The application must be able to accept interleaved data transfers if the Interlaken link partner transmits them on the Interlaken link. In this case, the Interlaken link partner must send traffic in Interleaved mode that conforms with the 50G Interlaken IP core BurstShort value.

Note: The transmitter (link partner) must only send packets with a minimum packet size of 64 bytes.