Article Details

ID: 1514
Case Type: faq
Category: Lattice IP/Reference Design
Related To: 10Gb+ Ethernet MAC
Family: All FPGA

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What effect does a PCS local/remote fault signal to the 10 Gb+ Ethernet MAC have on the MAC TX and RX logic?

The XAUI PCS communicates the local/remote link fault to the MAC via the XGMII RX data/control bus during the IDLE period, as defined by the IEEE specification. No other signals are used to communicate fault signaling.

When the RX MAC receives a fault sequence, the fault sequence in the receive pattern can only occur during the idle sequence between 2 RX frames as defined by the IEEE spec.

If the MAC receives a fault sequence, the TX and RX MAC logic will respond in the following manner:

  • MAC TX: The MAC completes the current frame transmission first before responding with an appropriate sequence.

  • MAC RX: If MAC receives a local fault, then the MAC RX logic drops the corresponding packet.