UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 15134

LogiCORE Gigabit Ethernet MAC - Auto-Negotiation support

Description

General Description:

Is auto-negotiation of link speed supported in the Gigabit Ethernet MAC Core? In other words, can the Core auto-negotiate between 10 Mbps, 100 Mbps, and 1 Gbps operation?

Solution

The Gigabit Ethernet MAC Core does not support link speed auto-negotiation since it only operates at 1 Gbps speeds. However, the Tri-mode Ethernet MAC Core does support this since it can operate at all three speeds: 10/100/1000 Mbps.

For the Gigabit Ethernet only Core, the Status Register (Reg 1) and the Extended Status Register (Reg 15) declare that the GMAC is only able to support 1000BASE-X. Auto-negotiation for 1000BASE-X is a new approach to auto-negotiation performance; this type of auto-negotiation cannot communicate with the older auto-negotiation protocol that is supported by 10/100 speed devices. Consequently, no mechanism exists that can negotiate link speed in the specifications for 1000BASE-X.

The only types of auto-negotiation supported by the GEMAC are the following:

- Auto-negotiation to determine whether a link partner supports Flow Control (this includes determining whether the partner is symmetric or asymmetric).

- Auto-negotiation to determine whether a link partner supports Half or Full Duplex operation.

These types are supported by the 1000BASE-X PCS/PMA version of the Core.

AR# 15134
Date Created 09/03/2007
Last Updated 12/15/2012
Status Active
Type General Article