ICS1892 Datasheet, PDF (41/148 Pages) Integrated Circuit Systems – 10Base-T/100Base-TX Integrated PHYceiver

ICS1892
Chapter 7 Functional Blocks
7.3 Functional Block: 100Base-X PCS and PMA Sublayers
Clause 24 of the ISO/IEC specification defines the 100Base-X Physical Coding sublayer (PCS) and
Physical Medium Attachment (PMA) sublayers. The ICS1892 is fully compliant with this clause in its
implementation.
7.3.1 PCS Sublayer
The ICS1892 100Base-X PCS sublayer provides two interfaces: one to a MAC/repeater and the other to
the ICS1892 PMA sublayer. In addition, it performs the transmit, receive, and control functions in
compliance with the ISO/IEC 8802-3 standard.
The ICS1892 100Base-X PCS PCS sublayer consists of the following:
• PCS Transmit sublayer, which provides the following:
– Parallel-to-serial conversion
– 4B/5B encoding
– Collision detection
• PCS Receive sublayer, which provides the following:
– Serial-to-parallel conversion
– 4B/5B encoding
– Carrier detection
– Code group framing
• Two PCS controls, which provide the following functions for the MAC/Repeater Interface:
– Assertion of the CRS carrier sense signal (which is part of the carrier sense modules)
– Assertion of the COL collision detection signal (which is part of the transmit modules)
Note:
When configured for 100M Symbol mode operations, the MAC/Repeater Interface bypasses most
of the PCS. When the ICS1892 MAC/Repeater Interface is in this mode, most of its PCS Transmit
and Receive modules are inactive. However, its PCS control functions (CRS and COL) remain
operational.
7.3.2 PMA Sublayer
The ICS1892 100Base-X PMA Sublayer consists of two interfaces: one to the Physical Coding sublayer
and the other to the Physical Medium Dependent sublayer. Functionally, the PMA sublayer is responsible
for the following:
• Link Monitoring
• Carrier Detection
• NRZI encoding/decoding
• Transmit Clock Synthesis
• Receive Clock Recovery
ICS1892, Rev. D, 2/26/01
© 2000-2001, Integrated Circuit Systems, Inc.
All rights reserved.
41
February 26, 2001