ICS1892
10Base-T/100Base-TX Integrated PHYceiver™
TSD
Chapter 5 Operating Modes Overview
ICS1892 Data Sheet
5.5 100Base-TX Operations
The ICS1892 100Base-TX mode is a primary operating mode that provides 100Base-TX physical layer
(PHY) services as defined in the ISO/IEC 8802-3 standard. In the 100Base-TX mode, the ICS1892 is a
100M translator between a MAC/repeater and the physical transmission medium. As such, the ICS1892
has two interfaces, both of which are fully configurable: one to the MAC/repeater and one to the Link
Segment. In 100Base-TX mode, the ICS1892 provides the following functions:
• Data conversion from both parallel-to-serial and serial-to-parallel formats
• Data encoding/decoding (4B/5B, NRZ/NRZI, and MLT-3)
• Data scrambling/descrambling
• Data transmission/reception over a twisted-pair medium
To accurately transmit and receive data, the ICS1892 employs DSP-based wave shaping, adaptive
equalization, and baseline wander correction. In addition, in 100Base-TX mode, the ICS1892 provides a
variety of control and status means to assist with Link Segment management. For more information on
100Base-TX, see Section 7.4, “Functional Block: 100Base-TX TP-PMD Operations”.
5.6 10Base-T Operations
The ICS1892 10Base-T mode is another primary operating mode that provides 10Base-T physical layer
(PHY) services as defined in the ISO/IEC 8802-3 standard. In the 10Base-T mode, the ICS1892 is a 10M
translator between a MAC/repeater and the physical transmission medium. As such, the ICS1892 has two
interfaces, both of which are fully configurable: one to the MAC/repeater and one to the Link Segment. In
10Base-T mode, the ICS1892 provides the following functions:
• Data conversion from both parallel-to-serial and serial-to-parallel formats
• Manchester data encoding/decoding
• Data transmission/reception over a twisted-pair medium
In addition, in 10Base-T mode, the ICS1892 provides a variety of control and status means to assist with
Link Segment management. For more information on 10Base-T, see Section 7.5, “Functional Block:
10Base-T Operations”.
5.7 Half-Duplex and Full-Duplex Operations
The ICS1892 supports half-duplex and full-duplex operations for both 10Base-T and 100Base-TX
applications. Full-duplex operation allows simultaneous transmission and reception of data, which
effectively doubles the Link Segment throughput to either 20 Mbps (for 10Base-T operations) or 200 Mbps
(for 100Base-TX operations).
As per the ISO/IEC standard, full-duplex operations differ slightly from half-duplex operations. These
differences are necessary, as during full-duplex operations a PHY actively uses both its transmit and
receive data paths simultaneously.
• In 10Base-T full-duplex operations, the ICS1892 disables its loopback function (that is, it does not
automatically loop back data from its transmitter to its receiver and disable its SQE Test function).
• In both 10Base-T and 100Base-TX full-duplex operations, the ICS1892 asserts its CRS signal only in
response to receive activity while its COL signal always remains inactive.
For more information on half-duplex and full-duplex operations, see the following sections:
• Section 8.2, “Register 0: Control Register”
• Section 8.2.8, “Duplex Mode (bit 0.8)”
• Section 8.3, “Register 1: Status Register”
• Section 8.6, “Register 4: Auto-Negotiation Register”
ICS1892, Rev. D, 2/26/01
February 26, 2001
© 2000-2001, Integrated Circuit Systems, Inc.
All rights reserved.
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IDT™ / ICS™ 10Base-T/100Base-TX Integrated PHYceiver™
ICS1892
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