ICS1892 Datasheet, PDF (39/148 Pages) Integrated Circuit Systems – 10Base-T/100Base-TX Integrated PHYceiver

ICS1892
Chapter 7 Functional Blocks
7.2.5 Auto-Negotiation: Progress Monitor
Under typical circumstances, the Auto-Negotiation sublayer can establish a connection with the ICS1892’s
remote link partner. However, some situations can prevent the auto-negotiation process from properly
achieving this goal. For these situations, the ICS1892 has an Auto-Negotiation Progress Monitor to provide
detailed status information to its Station Management (STA) entity. With this status information, the STA
can diagnose the failure mechanism and – in some situations – establish the link by correcting the problem.
When enabled, the auto-negotiation process typically requires less than 500 ms to execute, independent of
the link partner's ability to perform the auto-negotiation process. Typically, an STA polls both the
Auto-Negotiation Complete bit (bit 1.5) and the Link Status bit (bit 1.2) to determine when a link is
successfully established, either through auto-negotiation or parallel detection. The STA can then poll the
Auto-Negotiation Link Partner Ability Register and determine the highest-performance operating mode in
common with the capabilities it is advertising.
The ISO/IEC-defined priority table determines the established link type. As a simpler alternative, the STA
can read the QuickPoll Detailed Status Register and determine the link type from the Data Rate bit (bit
17.15) and the Duplex bit (bit 17.14). For convenience, the QuickPoll Register also includes the Link Status
bit (bit 17.0) and the Auto-Negotiation Complete bit (bit 17.4).
If (1) the auto-negotiation process does not complete, or (2) the link is not established, or (3) both the
auto-negotiation process does not complete and the link is not established, then the STA can determine the
cause of the link failure by using the outputs of the ICS1892 Auto-Negotiation Progress Monitor.
The Auto-Negotiation Progress Monitor provides the STA with four status bits of data to indicate both the
history and the present state of the auto-negotiation process. This status data is provided in the QuickPoll
Detailed Status register by using the Auto-Negotiation Complete bit (bit 17.4) as well as bits 17.13:11. The
bit order, from most-significant bit to least-significant bit, is 17.4, 17.13, 17.12, and 17.11. Using these four
bits, the Auto-Negotiation Progress Monitor provides nine state codes detailing the operation of the
auto-negotiation process for the STA. [For more information, see Section 8.12.3, “Auto-Negotiation
Progress Monitor (bits 17.13:11)”.]
The nine Auto-Negotiation Progress Monitor state codes are 0h through 8h and Fh. The Auto-Negotiation
Progress Monitor automatically latches the values of the Auto-Negotiation Arbitration State Machine into
the status bits only if the value of the present state is greater than the value that is currently in the status
bits.
ICS1892, Rev. D, 2/26/01
© 2000-2001, Integrated Circuit Systems, Inc.
All rights reserved.
39
February 26, 2001