The PHY drives the Receive Error signal ( phy_rx_er ) synchronously to phy_rx_clk . The PHY drives phy_rx_er for one or more phy_rx_clk periods to indicate that an error (such as a coding error or any error that the PHY is capable of detecting) was detected somewhere in the frame presently being transferred from the PHY to the AXI Ethernet Lite MAC .
The signal phy_rx_er should have no effect on the AXI Ethernet Lite MAC while phy_dv is deasserted. This Figure shows the behavior of phy_rx_er during frame reception with errors.
Table: Possible Values for phy_dv, phy_rx_er, and phy_rx_data[3:0] shows the possible combinations for the receive signals.