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AR# 23303

Embedded Tri-mode Ethernet MAC Wrapper v4.1 - Auto-Negotiation is unreliable

Description

During auto-negotiation the elastic buffer might under or overflow, but the Auto-Neg state machine in the EMAC should be aware of when this occurs and will temporarily freeze until the GT11 receiver PCS is reset and has recovered. The RXBUFERR pin from the GT11 is not wired up correctly to the EMAC in the v4.1 wrappers and can cause auto-negotiation to fail.

Solution

A patch is available to fix this issue. See (Xilinx Answer 22332) to download the patch.

Currently PHYEMAC#RXBUFSTATUS[1:0] is connected to the GT11 RXSTATUS[1:0]. To fix this, route RXBUFERR from the GT11 in question to the PHYEMAC#RXBUFSTATUS[1] input port of the Virtex-4 EMAC. PHYEMAC#RXBUFSTATUS[0] is unconnected in the EMAC and can be grounded.

AR# 23303
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article