CS89712-CB View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS89712-CB

High-Performance, Low-Power System-on-Chip with 10BASE-T Ethernet Controller

Cirrus Logic 

CS89712

2.36 Auto-Negotiation Considerations

The original IEEE 802.3 specification requires the

MAC to wait until 4 valid link-pulses are received

before asserting Link-OK. Any time an invalid

link-pulse is received, the count is restarted. When

auto-negotiation occurs, a transmitter sends FLP

(Fast Link Pulse) bursts instead of the original

IEEE 802.3 NLP (Normal Link Pulses).

If the hub is attempting to auto-negotiate with the

CS89712, the CS89712 will never get more than 1

"valid" link pulse (valid NLP). This is not a prob-

lem if the CS89712 is already sending link-pulses,

because when the hub receives NLPs from the

CS89712, the hub is required to stop sending FLPs

and start sending NLPs. The NLP transmitted by

the hub will put the CS89712 into Link-OK.

However, if the CS89712 is in Auto-Switch mode,

the CS89712 will never send any link-pulses, and

the hub will never change from sending FLPs to

sending NLPs.

DS502PP2

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