dm9301 ETC-unknow, dm9301 Datasheet - Page 13

• Manufacturer Part Number: dm9301
• Description: 100mbps Ethernet Fiber/twisted Pair Single Chip Media Converter
• Manufacturer: ETC-unknow

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 DM9301 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 125Mhz 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
Final
Version: DM9301-DS-F02
May 8, 2000
100Mbps Ethernet Fiber/Twisted Pair Single Chip Media Converter
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.
DM9301
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