LXT9782 datasheet(30/78 Pages) INTEL

30 / 78 page

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

Datasheet

• Allows a multi-port MAC/PHY communication with one system clock.

• Operates in both half and full duplex.

• Supports per-packet switching between 10 Mbps and 100 Mbps data rates.

The Serial MII operates at 125 MHz using a global reference clock and frame synchronization

signal (REFCLK and SYNC). Each port has an individual two-line data interface (TXDn and

RXDn). All signals are synchronous to REFCLK. Figure 13 is a simple SMII block diagram and

Table 10 summarizes the SMII signals.

Data is exchanged in 10-bit serial words. Each word contains one data byte (two nibbles of 4B

coded data) and two status bits. When the port is operating at 100 Mbps, each word contains a new

data byte. When the port is operating at 10 Mbps, each data byte is repeated 10 times.

Table 10. SMII Signal Summary

Signal

From

Purpose

TXD

PHY

MAC

Receive data & control

RXD

MAC

PHY

Transmit data & control

SYNC

PHY

MAC

Synchronization

REFCLK

MAC &

PHY

System

Synchronization

1. Refer to Table 1 on page 13 for detailed signal descriptions.

Figure 13. Simplified SMII Application Diagram

16 Port MAC

Clock

LXT9782

SYNC

CLOCK

LXT9782 Datasheet(PDF) 30 Page - Intel Corporation