80221 datasheet(22/91 Pages) LSI

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80220/80221

MD400159/E

3.13 LINK INTEGRITY & AUTONEGOTIATION

3.13.1 General

The 80220/80221 can be configured to implement either

the standard link integrity algorithms or the AutoNegotiation

algorithm.

The standard link integrity algorithms are used solely to

establish an active link to and from a remote device. There

are different standard link integrity algorithms for 10 and

100 Mbps modes. The AutoNegotiation algorithm is used

for two purposes: (1) To automatically configure the device

for either 10/100 Mbps and Half/Full Duplex modes, and

(2) to establish an active link to and from a remote device.

The standard link integrity and AutoNegotiation algorithms

are described below.

3.13.2 10Base-T Link Integrity Algorithm - 10Mbps

The 80220/80221 uses the same 10Base-T link intergrity

algorithm that is defined in IEEE 802.3 Clause 14. This

algorithm uses normal link pulses, referred to as NLP's and

transmitted during idle periods, to determine if a device

has successfully established a link with a remote device

(called Link Pass state). The transmit link pulse meets the

template defined in IEEE 802.3 Clause 14 and shown in

Figure 7. Refer to IEEE 802.3 Clause 14 for more details

if needed.

3.13.3 100Base-TX Link Integrity Algorithm -100Mbps

Since 100Base-TX is defined to have an active idle signal,

then there is no need to have separate link pulses like

those defined for 10Base-T. The 80220/80221 uses the

squelch criteria and descrambler synchronization algo-

rithm on the input data to determine if the device has

successfully established a link with a remote device (called

Link Pass state). Refer to IEEE 802.3 for both of these

algorithms for more details.

3.13.4 AutoNegotiation Algorithm

As stated previously, the AutoNegotiation algorithm is

used for two purposes: (1) To automatically configure the

device for either 10/100 Mbps and Half/Full Duplex modes,

and (2) to establish an active link to and from a remote

device. The AutoNegotiation algorithm is the same algo-

rithm that is defined in IEEE 802.3 Clause 28.

AutoNegotiation uses a burst of link pulses, called fast link

pulses and referred to as FLP's, to pass up to 16 bits of

signaling data back and forth between the 80220/80221

and a remote device. The transmit FLP pulses meet the

templated specified in IEEE 802.3 and shown in Figure 7.

A timing diagram contrasting NLP's and FLP's is shown in

Figure 8.

0 BT

1.3 BT

2.0 BT

4.0 BT

+50 mV

–50 mV

4.0 BT

42.0 BT

3.1 V

0.5 V/ns

0.5 BT

0.6 BT

300 mV

200 mV

585 mV

+50 mV

–50 mV

2.0 BT

0.85 BT

–3.1 V

0.25 BT

Figure 7. Link Pulse Output Voltage Template _ NLP, FLP

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