80220 Datasheet, PDF (23/91 Pages) LSI Computer Systems – 100BASE-TX/10BASE-T Ethernet Media Interface Adapter

80220/80221
The AutoNegotiation algorithm is initiated by any of the
following events: (1) Powerup, (2) device reset, (3) Au-
toNegotiation reset, (4) AutoNegotiation enabled, or (5) a
device enters the Link Fail State. Once a negotiation has
been initiated, the 80220/80221 first determines if the
remote device has AutoNegotiation capability. If the
remote device is not AutoNegotiation capable and is just
transmitting either a 10Base-T or 100Base-TX signal, the
80220/80221 will sense that and place itself in the correct
mode. If the 80220/80221 detects FLP's from the remote
device, then the remote device is determined to have
AutoNegotiation capability and the device then uses the
contents of the MI serial port AutoNegotiation Advertise-
ment register and FLP's to advertise its capabilities to a
remote device. The remote device does the same, and the
capabilities read back from the remote device are stored in
the MI serial port AutoNegotiation Remote End Capability
register. The 80220/80221 negotiation algorithm then
matches it's capabilities to the remote device's capabilities
and determines what mode the device should be config-
ured to according to the priority resolution algorithm de-
fined in IEEE 802.3 Clause 28. Once the negotiation
process is completed, the 80220/80221 then configures
itself for either 10 or 100 Mbps mode and either Full or Half
Duplex modes (depending on the outcome of the negotia-
tion process), and it switches to either the 100Base-TX or
10Base-T link integrity algorithms (depending on which
mode was enabled by AutoNegotiation). Refer to IEEE
802.3 Clause 28 for more details.
3.13.5 AutoNegotiation Outcome Indication
The outcome or result of the AutoNegotiation process is
stored in the speed detect and duplex detect bits in the MI
serial port Status Output register.
3.13.6 AutoNegotiation Status
The status of the AutoNegotiation process can be moni-
tored by reading the AutoNegotiation status bits in the MI
serial port Status register. The MI serial port Status
register contains a single AutoNegotiation acknowledge-
ment bit which indicates when an AutoNegotiation has
been initiated and successfully completed.
TX_DI±
a.) Normal Link Pulse (NLP)
TX_DI±
b.) Fast Link Pulse (FLP)
D0
D1
D2
D3
D14
D15
Clock Clock Clock Clock
Data Data Data Data
Clock Clock Clock
Data Data
Figure 8. NLP vs. FLP Link Pulse
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MD400159/E