Interlaken (2nd Generation) Intel® FPGA IP User Guide

ID 683396
Date 9/26/2022

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4.5.1. Interleaved and Packet Modes

You can configure the 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. 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 IP core parameter editor determines the IP core transmit mode.

Note: The Interlaken Look-aside feature transfers data only in packet mode. It does not support interleaved mode.

In Packet mode, the Interlaken IP core performs Optional Scheduling Enhancement based on Section 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 and BurstMin.

In Interleaved mode, you can achieve full capability of channelization and per-channel flow control offered by the Interlaken IP core. In this mode, you can interleave bursts of different channels. It allows more efficient use of bandwidth. The 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 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 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 confirms with the Interlaken IP core BurstShort value.

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