Features
• Supports Four 10/100/1000 Mbps Ethernet Ports with GMII/MII Interface
IEEE 802.3ab CSMA/CD Compliant
Full and Half Duplex Mode of Operation
Speed and Duplex Mode Auto-negotiation Through MDIO
Self-address Learning Mechanism Supports 512-MAC Addresses
Automatic Address Aging with 300 seconds Default
512-kbit Packet Buffer Memory Embedded
Serial Port Interface Employed to Communicate with MCU
IEEE 802.3ab Flow Control for Full Duplex Operation
Supports Store-and-Forward Mode of Operation
0.18 Micron, 1.8V CMOS Technology Packaged in 160-pin PQFP
3.3V I/O
Available in a Variety of Packages Depending on Customer Requirements
Description
This Layer 2 Switch provides an ideal solution for the design of unmanaged full wire-
speed multi-port Gigabit Ethernet (GbE) switches. Each port supports either
10/100/1000 Mbps data rate. Flow controls, back pressure in half-duplex mode and
PAUSE frame in full-duplex mode are employed to solve the HOL (Head of Line)
blocking.
This Layer 2 Switch integrates four half/full duplex mode 1000 BASE Gigabit Ethernet
MACs, wire speed switching engines, MAC address based address parsing algorithms
and packet buffer memory.
Figure 1. Ethernet Level 2 Switch Block Diagram
Switch
Fabric
Request
Control
Signals
Switch Core
Address Parse
Module
Packet Buffer
(48 kByte)
Management
Interface
(SPI, MDIO)
Mux
DataRate
FIFOGMI
MII
GMII
RXD
(RX_CLK)
TXD_nG
(TX_CLK)
TXD_G
(SYSCLK)
MAC0, 1, 2 & 3
SPI/MDIO
Address
Port Num
Packet Out
Packet In
Ack
4-port Layer 2
10/100/1000Mbps
Unmanaged
Switched Ethernet
Controller
AT79C1020
Summary
Note: This is a summary document. A complete document
is available under NDA. For more information, please con-
tact your local Atmel sales office.
3434BS–NETST–3/04