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DM9801E

1M Home Phoneline Network Physical Layer Single Chip Transceiver

Davicom Semiconductor, Inc. 

DM9801

1M Home Phoneline Network Physical Layer Single Chip Transceiver

Functional Description

The DM9801 is a single-chip Home Phoneline Network

transceiver .The DM9801 provides an IEEE 802.3u

subset Media Independent Interface (MII) or a pseudo-

standard General Purpose Serial Interface (GPSI).

The DM9801 enables home networking by allowing

Ethernet packets to be transported over common home

telephone wiring with no modifications, using Ethernet

CSMA/CD media access control procedures as defined in

the IEEE 802.3 standard. Figure 1 shows the major

functional blocks implemented in the DM9801.

RLL25

Encoder

Transmit

Timing

Generator

Muxed

GPSI or MII

Interface

Master PHY

Controller

RLL25

Decoder

HN Drivers

Receiver AFE

Receiver

and

Digital PLL

Figure 1

MII Interface

The DM9801 provides a subset Media Independent

Interface (MII) or a pseudo-standard General Purpose

Serial Interface (GPSI). The MII interface provides a

simple, easy way to implement connection between the

MAC Reconciliation layer and the DM9801 transceiver.

The MII is designed to make the differences between

various media transparent to the MAC sublayer.

The MII consists of a nibble wide receive data bus, a

nibble wide transmit data bus, and control signals to

facilitate data transfers between the PHY and the

Reconciliation layer.

TXD (transmit data) is a nibble (4 bits) of data that are

driven by the reconciliation sublayer synchronously with

respect to TX_CLK. For each TX_CLK period, which

TX_EN is asserted, TXD (3:0) are accepted for

transmission by the PHY.

TX_CLK (transmit clock) output to the MAC reconciliation

sublayer is a clock that provides the timing reference for

the transfer of the TX_EN, TXD, and TX_ER signals.

TX_EN (transmit enable) input from the MAC

reconciliation sublayer to indicate nibbles are being

presented on the MII for transmission on the physical

medium.

10

Preliminary

Version: DM9801-DS-P02

March 20, 2000

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