Aborting a Transmission - 2.3 English

Versal Devices Integrated 100G Multirate Ethernet MAC Subsystem Product Guide (PG314)

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2.3 English

As is the case in non-segmented operation, a packet can be aborted on the segmented interface either explicitly (asserting ERR) or implicitly (deasserting tvalid without first completing the affected frame).

The following diagram shows both cases. To keep the diagram compact, segments 0 and 2-5 are omitted. Assume they contain valid transactions.

Figure 1. AXI4-Stream Segmented Transmit Abort Transmission

In the figure, Frame A has started in cycle #4 (in Segment 0, not shown) and continues through to the end of Segment 5. An explicit frame transfer abort occurs in Segment 1 of cycle #5.

Next, a new frame (Frame B) begins in segment 1 of cycle #7, but this frame is aborted implicitly in cycle #8 when tx_axis_tvalid_0 is deasserted. The diagram ends with Frame C being transferred. It is acceptable to begin a new frame in the segment immediately following an aborted frame. There is no need for any idle bus segments.