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AR# 63961

10-Gigabit Ethernet PCS/PMA and AXI 10G Ethernet - 10GBASE-KR - UltraScale GTH - 2014.4.1 - Attribute update needed if using Auto-Negotiation

Description

The following applies If you are using 10GBASE-KR with Auto-Negotiation enabled in the 10-Gigabit Ethernet PCS/PMA or AXI 10G Ethernet core, and targeting UltraScale GTH.

There is an update to the UltraScale GTH attributes required to improve Auto-Negotiation performance and reliability across a backplane.  

The GTHE3 RXCDR_CFG2 bit 9 needs to change from a 1 to a 0.

Solution

In Vivado 2014.4.1 an XDC constraint can be added to the user XDC file make this change:

set_property RXCDR_CFG2 16'h05E6 [get_cells -hierarchical -filter {NAME=~ <core instance name>/*GTHE3_CHANNEL_PRIM_INST}]


For example, from the 10G PCS/PMA core Example Design itself (generated with shared logic in the example design), this becomes:
 

set_property RXCDR_CFG2 16'h05E6 [get_cells -hierarchical -filter {NAME=~ ten_gig_eth_pcs_pma_core_support_layer_i/ten_gig_eth_pcs_pma_i/*GTHE3_CHANNEL_PRIM_INST}]


With this set, Auto-Negotiation should complete quickly.
 

Without it set, Auto-Negotiation might require numerous restarts to complete and could therefore take several seconds.

In Vivado 2015.1, this constraint has been added to the core level XDC so that no user updates are required.  

AR# 63961
Date Created 03/19/2015
Last Updated 04/14/2015
Status Active
Type General Article
Devices
  • Kintex UltraScale
  • Virtex UltraScale
IP
  • AXI 10 Gigabit Ethernet
  • Ten Gigabit Ethernet PCS/PMA