ICS1893CF Data Sheet - Release
Chapter 7 Management Register Set
7.6.5 Technology Ability Field (bits 4.9:5)
When its Auto-Negotiation sublayer is enabled, the ICS1893CF transmits its link capabilities to its remote
link partner during the auto-negotiation process. The Technology Ability Field (TAF) bits 4.12:5 determine
the specific abilities that the ICS1893CF advertises. The ISO/IEC specification defines the TAF
technologies in Annex 28B.
The ISO/IEC specification reserves bits 4.12:10 for future use. When each of these reserved bits is:
• Read by an STA, the ICS1893CF returns a logic zero
• Written to by an STA, the STA must use the default value specified in this data sheet
ICS uses some reserved bits to invoke auxiliary functions. To ensure proper operation of the ICS1893CF,
an STA must maintain the default value of these bits. Therefore, ICS recommends that an STA always write
the default value of any reserved bits during all management register write operations.
Reserved bits 4.12:10 are Command Override Write (CW) bits. Whenever bit 16.15 (the Command
Register Override bit) is logic:
• Zero, the ICS1893CF isolates all STA writes to CW bits, including bits 4.12:10.
• One, an STA can modify the value of bits 4.12:10
Each of the bits 4.9:5 in the TAF represent a specific technology capability. When one of these bits is logic:
• Zero, it indicates to the remote link partner that the local device cannot support the technology
represented by the bit.
• One, it indicates to the remote link partner that the local device can support the technology.
With the exception of bit 4.9, the default settings of the TAF bits depend on the ICS1893CF operating
mode. Bit 4.9 is always logic zero, indicating that the ICS1893CF cannot support 100Base-T4 operations.
The TAF bits are Command Override Write bits. The default value of these bits depends on the signal level
on the HW/SW pin and whether the Auto-Negotiation sublayer is enabled.
With the Auto-Negotiation Enable bit (bit 0.12) set to logic:
• Zero (that is, disabled), the ICS1893CF does not execute the auto-negotiation process. Upon completion
of the initialization sequence, the ICS1893CF proceeds to the Idle state and begins transmitting IDLES.
Two Control Register bits – the Data Rate Select bit (bit 0.13) and the Duplex Select bit (bit 0.8) –
determine the technology mode that the ICS1893CF uses for data transmission and reception. In this
mode, the values of the TAF bits (bits 4.8:5) are undefined.
• One (that is, enabled), the ICS1893CF executes the auto-negotiation process and advertises its
capabilities to the remote link partner. The TAF bits (bits 4.8:5) determine the capabilities that the
ICS1893CF advertises to its remote link partner. For the ICS1893CF, all of these bits 4.8:5 are set to
logic one, indicating the ability of the ICS1893CF to provide these technologies.
Note:
1. The ICS1893CF does not alter the value of the Status Register bits based on the TAF bits in
register 4, as the ISO/IEC definitions for the Status Register bits require these bits to indicate all the
capabilities of the ICS1893CF.
2. The STA can alter the default TAF bit settings, 4.12:5, and subsequently issue an Auto-Negotiation
Restart.
7.6.6 Selector Field (Bits 4.4:0)
When its Auto-Negotiation Sublayer is enabled, the ICS1893CF transmits its link capabilities to its remote
Link Partner during the auto-negotiation process. The Selector Field is transmitted based on the value of
bits 4.4:0. These bits indicate to the remote link partner the type of message being sent during the
auto-negotiation process. The ICS1893CF supports IEEE Std. 802.3, represented by a value of 00001b in
bits 4.4:0. The ISO/IEC 8802-3 standard defines the Selector Field technologies in Annex 28A.
ICS1893CF, Rev. F, 03/01/07
Mar. 2007
Copyright © 2007, Integrated Device Technology, Inc.
All rights reserved.
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ICSI [ INTEGRATED CIRCUIT SOLUTION INC ]
