DM9101
10/100Mbps Ethernet Physical Layer Single Chip Transceiver
The DM9101 performs all PCS (Physical Coding
Sublayer), PMA (Physical Media Access), TP-PMD
(Twisted Pair Physical Medium Dependent) sublayer,
10Base-T Encoder/Decoder, and Twisted Pair Media
Access Unit (TPMAU) functions. Figure 1 shows the major
functional blocks implemented in the DM9101.
Functional Description
The DM9101 Fast Ethernet single-chip transceiver,
provides the functionality as specified in IEEE 802.3u,
integrates a complete 100Base-TX module and a
complete 10Base-T module. The DM9101 provides a
Media Independent Interface (MII) as defined in the IEEE
802.3u standard (Clause 22).
100Base-TX
Transmitter
100Base-TX
Receiver
10Base-T
Tranceiver
MII Interface
Carrier
Sense
Collision
Detection
Auto
Negotiation
MII Serial
Management
Interface
Figure 1
•
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.
MII Interface
The DM 9101 provides a Media Independent Interface (MII)
as defined in the IEEE 802.3u standard (Clause 22).
The purpose of the MII interface is to provide a simple, easy
to implement connection between the MAC Reconciliation
layer and the PHY. 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 facilitatedata
transfers between the PHY and the Reconciliation layer.
•
•
TX_CLK (transmit clock) output to the MAC
reconciliation sublayer is a continuous 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.
12
Final
Version: DM9101-DS-F03
July 22, 1999
ETC [ ETC ]
