DM9301FP datasheet(13/22 Pages) DAVICOM

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DM9301FP

100Mbps Ethernet Fiber/Twisted Pair Single Chip Media Converter

Final

Version: DM9301FP-DS-F03

June 06, 2007

Therefore, the compensation or equalization must be

adaptive to ensure proper conditioning of the received

signal independent of the cable length.

TX MLT-3 to NRZI Decoder

The DM9301FP decodes the MLT-3 information from the

TX Digital Adaptive Equalizer into NRZI data.

TX Clock Recovery Module

The TX Clock Recovery Module accepts NRZI data

from the MLT-3 to NRZI decoder. The TX Clock

Recovery Module locks onto the data stream and

extracts the 125 MHz reference clock. The

extracted and synchronized clock and data are

presented to the NRZI to NRZ Decoder.

TX NRZI to NRZ Decoder

The TX transmit data stream is required to be NRZI

encoded in for compatibility with the TP-PMD

standard for 100Base-TX transmission over

Category-5 unshielded twisted pair cable. This

conversion process must be reversed on the

receive end. The NRZI to NRZ decoder receives the

NRZI data stream from the TX Clock Recovery

Module and converts it to a NRZ data stream to be

presented to the TX Serial to Parallel conversion

block.

TX Serial to Parallel Converter

The TX Serial to Parallel converter receives a serial

data stream from the TX NRZI to NRZ decoder, and

converts the data stream to parallel data to be

presented to the TX descrambler. The parallel data

format presented to the TX descrambler is 5B

coded.

TX Code Group Monitor

The TX Code Group Alignment block receives non-

aligned 5B data from the TX descrambler and

monitors it for 5B code group violations. TX Code

Group Alignment occurs after the J/K is detected,

and subsequent data is monitored on a fixed

boundary. If a violation is detected, the TX Code

Group Monitor block signals the error to the Link

Status Monitor block. In turn, the Link Status

Monitor block flashes the TX error LED

(TXERRLED#).

TX Descrambler

Because of the scrambling process required to

control the radiated emissions of transmit data

streams, the receiver must descramble the receive

data streams. The TX Descrambler receives

scrambled parallel data streams from the Serial to

Parallel converter, descrambles the data streams,

and presents the data streams to the Code Group

alignment block.

FX Parallel to Serial Converter

The FX Parallel to Serial Converter receives parallel

5B data from the TX de-scrambler and serializes it

(converts it from a parallel to a serial data stream).

The serialized data stream is then presented to the

FX NRZ to NRZI Encoder block

FX NRZ to NRZI Encoder

After the transmit data stream has been serialized,

the data must be NRZI encoded for compatibility

with the standard for 100Base-FX.

Link Monitor and LED Driver

The Link Monitor block monitors both the TX and

FX interfaces for link active, receive data and erring

5-bit stream.

The Link Monitor has the ability to detect each

interfaces link status. The TX will transmit either an

idle symbol or a Halt symbol if the FX link is not

established. Conversely the FX will transmit either

an idle symbol or a Halt symbol if the TX link is not

established. When an o Link” condition exists, the

interface pin called LTNOLNK” will cause Halt

symbols to be transmitted instead of idle symbols.

The link active LED is a static indication of the TX

and FX links. It will be true to indicate the presence

of a link. The receive data and error LED are

generated through a ne-Shot” so that even the

smallest receive or error condition will be indicated.

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