R

Chapter 9: Configuration and Status

Table 9-20:SGMII Status (Register 1) (Continued)

Bit(s)

Name

Description

Attributes

Default

Value

 

 

 

 

 

 

 

 

 

1.7

Unidirectional

Always returns ‘1,’ writes ignored

returns 1

1

 

Ability

 

 

 

 

 

 

 

 

1.6

MF Preamble

Always returns a ‘1’ for this bit to indicate

returns 1

1

 

Suppression

that Management Frame Preamble

 

 

 

 

Suppression is supported

 

 

 

 

 

 

 

1.5

Auto- Negotiation

1 = Auto-Negotiation process completed

read only

0

 

Complete

across SGMII link

 

 

 

 

0 = Auto-Negotiation process not

 

 

 

 

completed across SGMII link

 

 

 

 

 

 

 

1.4

Remote Fault

1 = A fault on the Medium has been

read only

0

 

 

detected

self

 

 

 

 

 

 

 

0 = No fault of the Medium has been

clearing

 

 

 

detected

on read

 

 

 

 

 

 

1.3

Auto- Negotiation

Always returns a ‘1’ for this bit to indicate

returns 1

1

 

Ability

that the SGMII core is capable of Auto-

 

 

 

 

Negotiation

 

 

 

 

 

 

 

1.2

SGMII Link Status1

1 = SGMII Link is up

read only

0

 

 

0 = SGMII Link is down

self

 

 

 

Latches '0' if SGMII Link Status goes

clearing

 

 

 

on read

 

 

 

down. Clears to current SGMII Link

 

 

 

 

 

 

 

Status on read.

 

 

 

 

See table note for SGMII Link Status

 

 

 

 

behavior.

 

 

 

 

 

 

 

1.1

Jabber Detect

Always returns a ‘0’ for this bit since

returns 0

0

 

 

Jabber Detect is not supported

 

 

 

 

 

 

 

1.0

Extended Capability

Always returns a ‘0’ for this bit because no

returns 0

0

 

 

extended register set is supported

 

 

 

 

 

 

 

1.When high, the link is valid: synchronization of the SGMII link has been obtained and SGMII Auto-Negotiation (if present and enabled) has completed.

When low, a valid link has not been established. Either SGMII link synchronization has failed or SGMII Auto-Negotiation (if present and enabled) has failed to complete.

Regardless of whether SGMII Auto-Negotiation is enabled or disabled, there can be some delay to the deassertion of this signal following the loss of synchronization of a previously successful SGMII link. This is due to the Auto-Negotiation state machine which requires that synchronization is lost for an entire link timer duration before changing state. For more information, see the 802.3 specification.

138

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Ethernet 1000BASE-X PCS/PMA or SGMII v9.1

 

 

UG155 March 24, 2008

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Xilinx 1000BASE-X manual Configuration and Status 20SGMII Status Register