82583V Datasheet, PDF (98/374 Pages) Intel Corporation – Intel® 82583V GbE Controller

82583V GbE Controller—Interconnects
6.2.3.1
6.2.3.1.1
Note:
Note:
Note:
The PHY performs auto-negotiation per 802.3ab clause 40 and extensions to clause 28.
Link resolution is obtained by the MAC from the PHY after the link has been established.
The MAC accomplishes this via the MDIO interface, via specific signals from the PHY to
the MAC, or by MAC auto-detection functions.
Link Configuration
Link configuration is generally determined by PHY auto-negotiation. The software
device driver must intervene in cases where a successful link is not negotiated or a user
desires to manually configure the link. The following sections discuss the methods of
link configuration for copper PHY operation.
PHY Auto-Negotiation (Speed, Duplex, Flow-Control)
The PHY performs the auto-negotiation function. The details of this operation are
described in the IEEE P802.3ab draft standard and are not included here.
Auto-negotiation provides a method for two link partners to exchange information in a
systematic manner in order to establish a link configuration providing the highest
common level of functionality supported by both partners. Once configured, the link
partners exchange configuration information to resolve link settings such as:
• Speed: 10/100/1000 Mb/s
• Duplex: full or half
• Flow control operation
PHY specific information required for establishing the link is also exchanged.
If flow control is enabled in the 82583V, the settings for the desired flow control
behavior must be set by software in the PHY registers and auto-negotiation restarted.
After auto-negotiation completes, the software device driver must read the PHY
registers to determine the resolved flow control behavior of the link and reflect these in
the MAC register settings (CTRL.TFCE and CTRL.RFCE). If no software device driver is
loaded and auto-negotiation is enabled, then hardware sets these bits in accordance
with the auto-negotiation results.
By default, the PHY advertises flow control support.
Once PHY auto-negotiation completes, the PHY asserts a link indication (LINK) to the
MAC. Software must set the Set Link Up bit in the Device Control register (CTRL.SLU)
before the MAC recognizes the link indication from the PHY and can consider the link to
be up.
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