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Altera_Forum's avatar
Altera_Forum
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13 years ago

Ethernet autonegotiation

I am just wondering what kind of procedures are running during the link establishment in 100Base-T ethernet in case auto negotiation is disabled (i.e. forced mode) at both ends of the ethernet con...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Actually the MAC itself always has to be told whether to do FDX or HDX, the driver has to extract that information from the PHY (or ignore the PHY and use a hard-coded value).

The PHY configuration (and negotiation) control the speed. In some cases (eg some MAC using MII) the MAC doesn't need to know whether the PHY is doing 10M or 100M (I'm not sure about higher speeds).

(I suspect we are agreeing violently!)