ICS1893BF Data Sheet Rev. E - Release
Chapter 3 Overview of the ICS1893BF
3.1 100Base-TX Operation
During 100Base-TX data transmission, the ICS1893BF accepts packets from a MAC and inserts
Start-of-Stream Delimiters (SSDs) and End-of-Stream Delimiters (ESDs) into the data stream. The
ICS1893BF encapsulates each MAC frame, including the preamble, with an SSD and an ESD. As per the
ISO/IEC Standard, the ICS1893BF replaces the first octet of each MAC preamble with an SSD and
appends an ESD to the end of each MAC frame.
When receiving data from the medium, the ICS1893BF removes each SSD and replaces it with the
pre-defined preamble pattern before presenting the nibbles to its MAC Interface. When the ICS1893BF
encounters an ESD in the received data stream, signifying the end of the frame, it ends the presentation of
nibbles to its MAC Interface. Therefore, the local MAC receives an unaltered copy of the transmitted frame
sent by the remote MAC.
During periods when MAC frames are being neither transmitted nor received, the ICS1893BF signals and
detects the IDLE condition on the Link Segment. In the 100Base-TX mode, the ICS1893BF transmit
channel sends a continuous stream of scrambled ones to signify the IDLE condition. Similarly, the
ICS1893BF receive channel continually monitors its data stream and looks for a pattern of scrambled ones.
The results of this signaling and monitoring provide the ICS1893BF with the means to establish the integrity
of the Link Segment between itself and its remote link partner and inform its Station Management Entity
(STA) of the link status.
For 100M data transmission, the ICS1893BF MAC Interface is configured to provide a 100M Media
Independent Interface (MII).
3.2 10Base-T Operation
During 10Base-T data transmission, the ICS1893BF inserts only the IDL delimiter into the data stream. The
ICS1893BF appends the IDL delimiter to the end of each MAC frame. However, since the 10Base-T
preamble already has a Start-of-Frame delimiter (SFD), it is not required that the ICS1893BF insert an
SSD-like delimiter.
When receiving data from the medium (such as a twisted-pair cable), the ICS1893BF uses the preamble to
synchronize its receive clock. When the ICS1893BF receive clock establishes lock, it presents the
preamble nibbles to its MAC Interface. The 10M MAC Interface uses the standard MII Interface.
In 10M operations, during periods when MAC frames are being neither transmitted nor received, the
ICS1893BF signals and detects Normal Link Pulses. This action allows the integrity of the Link Segment
with the remote link partner to be established and then reported to the ICS1893BF’s STA.
ICS1893BF, Rev. E, 8/11/09
August, 2009
Copyright © 2009, IDT, Inc.
All rights reserved.
15
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
