ICS1892 Datasheet, PDF (21/148 Pages) Integrated Circuit Systems – 10Base-T/100Base-TX Integrated PHYceiver

ICS1892
Chapter 5 Operating Modes Overview
5.3 Automatic Power-Saving Operations
The ICS1892 has power-saving features that automatically minimize its total power consumption while it is
operating. Table 5-1 lists the ICS1892 automatic power-saving features for the various modes.
Table 5-1. Automatic Power-Saving Features, 10Base-T and 100Base-TX Modes
Power-
Saving
Feature
10Base-T Mode
Mode for ICS1892
100Base-TX Mode
Disable Inter- In 10Base-T mode, the ICS1892 disables In 100Base-TX mode, the ICS1892
nal Modules all its internal 100Base-TX modules.
disables all its internal 10Base-T modules.
STA Control
of Automatic
Power-
Saving
Features
When an STA sets the state of the ICS1892
Extended Control Register 2, bit 19.0 to
logic:
• Zero, the 100Base-TX modules always
remain enabled, even during 10Base-T
operations.
• One, the ICS1892 automatically
disables 100Base-TX modules while the
ICS1892 is operating in 10Base-T
mode.
When an STA sets the state of the ICS1892
Extended Control Register 2, bit 19.1 to
logic:
• Zero, the 10Base-T modules always
remain enabled, even during
100Base-TX operations.
• One, the ICS1892 automatically
disables 10Base-T modules while the
ICS1892 is operating in 100Base-TX
mode.
5.4 Auto-Negotiation Operations
The ICS1892 has an Auto-Negotiation sublayer. It provides both an input pin, ANSEL (Auto-Negotiation
Select) and a Control Register bit (bit 0.12) to determine whether its Auto-Negotiation sublayer is enabled
or disabled. The ICS1892 HW/SW input pin exclusively selects whether the ANSEL pin (which is used for
the hardware mode) or Control Register bit 0.12 (which is used for the software mode) controls its
Auto-Negotiation sublayer.
When enabled, the ICS1892 Auto-Negotiation sublayer exchanges technology capability data with its
remote link partner and automatically selects the highest-performance operating mode it has in common
with its remote link partner. For example, if the ICS1892 supports 100Base-TX and 10Base-T modes – but
its link partner supports 100Base-TX and 100Base-T4 modes – the two devices automatically select
100Base-TX as the highest-performance common operating mode. For details regarding initialization and
control of the auto-negotiation process, see Section 7.2, “Functional Block: Auto-Negotiation”.
ICS1892, Rev. D, 2/26/01
© 2000-2001, Integrated Circuit Systems, Inc.
All rights reserved.
21
February 26, 2001