描述

The AXI Ethernet lite IP always has buffers instantiated in the netlists. 

When the C_INCLUDE_GLOBAL_BUFFER parameter is set, BUFGs are used and when not, IBUFs are used instead.

解决方案

Note: It is recommended that the EDK system be added as a sub-module in the ISE or PlanAhead flow so that the buffers are used appropriately by the tools. 

This answer record describes a work-around for the use-case where the EDK design is instantiated using netlists rather than the recommended flow.

1. Copy the axi_ethernetlite_v1_01_b IP from the install area ($XILINX_EDK\hw\XilinxProcessorIPLib\pcores\axi_ethernetlite_v1_01_b) to a local repository.
    
2. Edit the MPD file and remove the BUFFER_TYPE = IBUF tags