ICS1893Y-10 Datasheet, PDF (79/150 Pages) –

ICS1893Y-10 - Release
Chapter 7 Management Register Set
7.6.5 Technology Ability Field (bits 4.9:5)
When its Auto-Negotiation sublayer is enabled, the ICS1893Y-10 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 ICS1893Y-10 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 ICS1893Y-10 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 ICS1893Y-10,
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 ICS1893Y-10 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 ICS1893Y-10 operating
mode. Bit 4.9 is always logic zero, indicating that the ICS1893Y-10 cannot support 100Base-T4 operations.
7.6.5.1 Technology Ability Field: Hardware Mode
When the ICS1893Y-10 is operating in hardware mode (that is, the HW/SW pin is logic zero), these TAF
bits are Read-Only 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.
In hardware mode, with the ANSEL pin pulled:
• Low to a disabled state, the ICS1893Y-10 does not execute the auto-negotiation process. Upon
completion of the initialization sequence, the ICS1893Y-10 proceeds to the idle state and begins
‘sending idles’ according to the technology mode selected by the 10/100SEL pin and the DPXSEL pin. In
this mode, the values of the TAF bits (bits 4.8:5) are undefined.
• High to an enabled state, the ICS1893Y-10 executes the auto-negotiation process and advertises its
capabilities to the remote link partner immediately following reset. The 10/100SEL and DPXSEL input
pins determine the single capability that the ICS1893Y-10 advertises. The ICS1893Y-10 updates the
Auto-Negotiation Advertisement Register TAF field to indicate the selection made by these pins. The
ICS1893Y-10 sets only one of these four bits to logic one. The other three bits are a logic zero.
Note: The ICS1893Y-10 does not alter the value of the Status Register bits. Although the
ICS1893Y-10 is advertising only one technology, the ISO/IEC definitions for the Status
Register bits require these bits to indicate all the capabilities of the ICS1893Y-10.
ICS1893Y-10 Rev F 1/20/04
Copyright © 2004, Integrated Circuit Systems, Inc.
All rights reserved.
79
January, 2004