RTL8201(L)
2002-01-18
Rev.1.04
17
7. Functional Description
The RTL8201(L) Phyceiver is a physical layer device that integrates 10Base-T and 100Base-TX functions and some extra
power manage features into a 48 pin single chip which is used in 10/100 Fast Ethernet applications. This device supports the
following functions:
MII interface with MDC/MDIO management interface to communicate with MAC
IEEE 802.3u clause 28 Auto-Negotiation ability
Flow control ability support to cooperate with MAC
Speed, duplex, auto-negotiation ability configurable by hard wire or MDC/MDIO.
Flexible LED configuration.
7-wire SNI(Serial Network Interface) support, works only on 10Mbps mode.
Power Down mode support
4B/5B transform
Scrambling/De-scrambling
NRZ to NRZI, NRZI to MLT3
Manchester Encode and Decode for 10 BaseT operation
Clock and Data recovery
Adaptive Equalization
7.1 MII and Management Interface
To set the RTL8201(L) for MII mode operation, pull MII/SNIB pin high and properly set the ANE, SPEED, and DUPLEX
pins.
The MII (Media Independent Interface) is an 18-signal interface which is described in IEEE 802.3u supplying a standard
interface between PHY and MAC layer. This interface operates in two frequencies – 25Mhz and 2.5Mhz to support
100Mbps/10Mbps bandwidth for both the transmit and receive function. While transmitting packets, the MAC will first assert
the TXEN signal and change byte data into 4 bits nibble and pass to the PHY by TXD[0..3]. PHY will sample TXD[0..]
synchronously with TXC — the transmit clock signal supplied by PHY – during the interval TXEN is asserted. While
receiving a packet, the PHY will assert the RXEN signal, pass the received nibble data RXD[0..3] clocked by RXC, which is
recovered from the received data. CRS and COL signals are used for collision detection and handling.
The MAC layer device can control PHY by the MDC/MDIO management interface, but for proper operation, the PHY address
needs to be well configured so the management command can be delivered to the PHY. The MDC can be software generated
to clock the 1 bit serial data stream to/from the MDIO to access the registers of the PHY.
In 100Base-TX mode, when decoded signal in 5B is not IDLE, the CRS signal will assert and when 5B is recognized as IDLE
it will be de-asserted. In 10Base-T mode, CRS will assert when the 10M preamble been confirmed and will be de-asserted
when the IDLE pattern been confirmed.
The RXDV signal will be asserted when decoded 5B are /J/K/and will be deasserted if the 5B are /T/R/or IDLE in 100Mbps
mode. In 10Mbps mode, the RXDV signal is the same as the CRS signal.
The RTL8201(L) does not use the TXER signal and will not affect the transmit function.
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