LXT9782 datasheet(39/78 Pages) INTEL

39 / 78 page

Fast Ethernet 10/100 Multi-Port Transceiver with Serial MII — LXT9762/9782

Datasheet

Polarity Correction

The LXT97x2 automatically detects and corrects for receive signal (TPIP/N) inversion. Reversed

polarity is detected if eight inverted link pulses, or four inverted EOF markers, are received

consecutively. If link pulses or data are not received by the maximum receive time-out period, the

polarity converter resets to a non-inverted state.

Fiber PMD Sublayer

The LXT97x2 provides a PECL interface for connection to an external fiber-optic transceiver.

(The external transceiver provides the PMD function for fiber media.) The LXT97x2 uses an

NRZI format for the fiber interface. The fiber interface operates at 100 Mbps and does not support

10FL applications.

Far End Fault Indications

The LXT97x2 Signal Detect pins receive signal fault indications from local fiber transceivers via

the SD pins. The device can also detect far end fault code in the received data stream. The

LXT97x2 “ORs” both fault conditions to set bit 1.4. Bit 1.4 is set once and clears when read.

Either fault condition causes the LXT97x2 to drop the link unless Forced Link Pass is selected

(16.14 = 1). Link down condition is then reported via interrupts and status bits.

In response to locally detected signal faults (SD activated by the local fiber transceiver), the

affected port can transmit the far end fault code if fault code transmission is enabled by bit 16.2.

• When bit 16.2 = 1, transmission of the far end fault code is enabled. The LXT97x2 transmits

far end fault code if fault conditions are detected by the Signal Detect pins.

• When bit 16.2 = 0, the LXT97x2 does not transmit far end fault code. It continues to transmit

idle code and may or may not drop link depending on the setting for bit 16.14.

2.8

10 Mbps Operation

The LXT97x2 operates as a standard 10BASE-T transceiver. Data transmitted by the MAC is

Manchester-encoded, and transmitted on the TPOP/N outputs. Received data is decoded and

passed to the MAC. The LXT97x2 supports all the standard 10 Mbps functions.

During 10BASE-T (10T) operation, the LXT97x2 transmits and receives Manchester-encoded data

across the network link. When the MAC is not actively transmitting data, the LXT97x2 sends out

link pulses on the line.

In 10T mode, the polynomial scrambler/descrambler is inactive. Manchester-encoded signals

received from the network are decoded by the LXT97x2 and sent across the MII to the MAC.

The LXT97x2 does not support fiber connections at 10 Mbps.

LXT9782 датащи(PDF) 39 Page - Intel Corporation