Keywords: TEMAC, EMAC, 1G, 1000 mb/s, 100 mb/s, 10 mb/s, rate, AN, Auto, negotiation
When using the soft Tri-Mode Ethernet MAC core, or the Virtex-4 and Virtex-5 Embedded Tri-Mode Ethernet MAC block, how is the speed of the MAC set when connecting to a PHY that is Auto-Negotiating the speed?
The speed can be set by the user application after Auto-Negotiation completes by doing the following:
1. The user application can either monitor an Auto Negotiation Interrupt from the PHY or SGMII core, or Poll for Auto Negotiation to complete via MDIO. The MDIO interface can be connected to through the TEMAC host interface.
2. Once Auto Negotiation completes the user application can read the MDIO Auto-Negotiation registers to obtain the negotiated speed.
3. The user application will then need to set this speed in the TEMAC configuration registers via the host interface.
The example designs provided with the cores currently do not have synthesizable hdl code to implement this.
This applies to both applications using an MII/GMII/RGMII interface to an External PHY and using SGMII to interface to an External PHY. When using SGMII with either the Embedded TEMAC or the soft 1000 BASE-X PCS/PMA or SGMII LogiCORE Auto-Negotiation is monitored with the internal SGMII MDIO registers.