ICS1893 datasheet(70/152 Pages) ICST

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ICS1893 Rev C 6/6/00

June, 2000

Chapter 8

Management Register Set

ICS1893 Data Sheet - Release

8.3.9

Remote Fault (bit 1.4)

An STA reads bit 1.4 to determine if a Remote Fault exists. The ICS1893 sets bit 1.4 based on the Remote

Fault bit received from its remote link partner. The ICS1893 receives the Remote Fault bit as part of the

Link Code Word exchanged during the auto-negotiation process. If the ICS1893 receives a Link Code

Word from its remote link partner and the Remote Fault bit is set to:

• Zero, then the ICS1893 sets bit 1.4 to logic zero.

• One, then the ICS1893 sets bit 1.4 to logic one. In this case, the remote link partner is reporting the

detection of a fault, which typically occurs when the remote link partner is having a problem with its

receive channel.

Bit 1.4 is a latching high status bit. (For more information on latching high and latching low bits, see Section

8.1.4.1, “Latching High Bits”and Section 8.1.4.2, “Latching Low Bits”.)

Note:

The ICS1893 has two versions of the Remote Fault bit.

• One version of the Remote Fault bit is a latching high version. An STA can access this version

through either Management Register 1 (bit 1.4) or 17 (bit 17.1). This bit 1.4/17.1 is cleared when

an STA reads either of these registers. (Bit 1.4 is identical to bit 17.1 in that they are the same

internal bit.)

• Another version of the Remote Fault bit is updated whenever the ICS1893 receives a new Link

Control Word. An STA can access this version through Management Register 5 (bit 5.13), which

like bits 1.4/17.1, also reports the status of the Remote Fault bit received from the remote link

partner. However, bit 5.13 is not a latching high bit.

The operation of both bit 1.4/17.1 and bit 5.13 are in compliance with the IEEE Std 802.3u.

8.3.10

Auto-Negotiation Ability (bit 1.3)

The STA reads bit 1.3 to determine if the ICS1893 can support the auto-negotiation process. If the

ICS1893:

• Cannot support the auto-negotiation process, it clears bit 1.3 to logic zero.

• Can support the auto-negotiation process, it sets bit 1.3 to logic one. (For the ICS1893, the default value

of bit 1.3 is logic one.)

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