LXT9763 — Fast Ethernet 10/100 Hex Transceiver with Full MII
1.8
Establishing Link
See Figure 10 for an overview of link establishment.
1.8.1
Auto-Negotiation
The LXT9763 attempts to auto-negotiate with its counter-part across the link by sending Fast Link
Pulse (FLP) bursts. Each burst consists of 33 link pulses spaced 62.5 µs apart. Odd link pulses
(clock pulses) are always present. Even link pulses (data pulses) may be present or absent to
indicate a “1” or a “0”. Each FLP burst exchanges 16 bits of data, which are referred to as a
“page”. All devices that support auto-negotiation must implement the “Base Page” defined by
IEEE 802.3 (registers 4 and 5). LXT9763 also supports the optional ‘Next Page’ function
(registers 7 and 8).
1.8.1.1
Base Page Exchange
By exchanging Base Pages, the LXT9763 and its link partner communicate their capabilities to
each other. Both sides must receive at least three identical base pages for negotiation to proceed.
Each side finds the highest common capabilities that both sides support. Both sides then exchange
more pages, and finally agree on the operating state of the line.
1.8.1.2
1.8.1.3
Next Page Exchange
Additional information, above that required by base page exchange is also sent via “Next Pages’.
The LXT9763 fully supports the 802.3 method of negotiation via Next Page exchange.
Controlling Auto-Negotiation
When auto-negotiation is controlled by software, the following steps are recommended:
• After power-up, power-down, or reset, the power-down recovery time, (see Table 34 on
page 57), must be exhausted before proceeding.
• Set the auto-negotiation advertisement bits.
• Enable auto-negotiation (set MDIO bit 0.12 = 1).
Note: Do not enable Auto-Negotiation if fiber mode is selected.
1.8.1.4
Parallel Detection
In parallel with auto-negotiation, the LXT9763 also monitors for 10 Mbps Normal Link Pulses
(NLP) or 100 Mbps Idle symbols. If either is detected, the device automatically reverts to the
corresponding operating mode. Parallel detection allows the LXT9763 to communicate with
devices that do not support auto-negotiation.
24
Datasheet
INTEL [ INTEL ]
