ICS1893 datasheet(44/152 Pages) ICST

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ICS1893 Rev C 6/6/00

June, 2000

Chapter 7

Functional Blocks

ICS1893 Data Sheet - Release

7.3

Functional Block: 100Base-X PCS and PMA Sublayers

The ICS1893 is fully compliant with clause 24 of the ISO/IEC specification, which defines the 100Base-X

Physical Coding sublayer (PCS) and Physical Medium Attachment (PMA) sublayers.

7.3.1

PCS Sublayer

The ICS1893 100Base-X PCS sublayer provides two interfaces: one to a MAC/repeater and the other to

the ICS1893 PMA sublayer. An ICS1893’s PCS sublayer performs the transmit, receive, and control

functions and 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

• PCS control functions, which provide:

– Assertion of the CRS (carrier sense) signal

– Assertion of the COL (collision detection) signal

Note:

When configured for 100M Symbol mode operations, the MAC/Repeater Interface bypasses most

of the PCS. When the ICS1893 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 ICS1893 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

ICS1893 датащи(PDF) 44 Page - Integrated Circuit Systems