General Description
The DM8108 is an 8 port 10/100Mbit/s nonblocking Ethernet switch with on-chip address-lookup engine. The DM8108 provides a low-cost, high-performance switch solution with PHYs and single SGRAM.

FEATUREs
■ Low cost Fast Ethernet Switching Controller.
 • Provide packet switching functions between eight 10/100Mbps, auto-negotiated on-chip Fast Ethernet ports and a proprietary Full-duplex Expansion port.
 • Cascade max. 8 DM8108s without extra glue logic for 64-port configuration.
■ Incorporates three 802.3 compliant 10/100Mbps Media Access Controllers
 • Direct interface to MII (Media Independent Interface)
 • Half/Full Duplex Support for individual port (upto 200Mbps/port)
 • IEEE 802.3 100Base-TX, T4.FX compatible
■ Auto-negotiation supported through Serial MII interface
■ High-performance Distributed Switching Engine
 • Performs packet forwarding and filtering at full wire-speed
 • 148,800 packets/sec. on each Ethernet port
■ Direct support for packet buffering
 • Glue-less interface with 1 or 2 Mbytes of SDRAM (SGRAM)
 • 32 bit memory bus configuration
 • 66 Mhz – 90Mhz memory bus speed
 • Up-to 1.1K buffers, 1536-byte each, allocated to receive ports
■ Support Store and Forward switching approach
 • Low last-bit to first-bit out delay
 • Allow mixed speed Ethernet packet switching
 • Allow conversion between different protocols
■ Flow control
 • Support partitioning function
 • Support back-pressure while lack of internal resources
 • Support 802.3x PAUSE function in full duplex mode
 • Support up to 4-port trunking for 800Mbps bandwidth
■ Advanced Address Learning and Searching
 • Self learning mechanism
 • Cache 128 address entries internally
 • Record up-to 16K Uni-cast MAC addresses and unlimited Multicast and Broadcast addresses
 • Automatic aging scheme
 • Broadcast filtering rate control
■ Expansion Bus
 • Up-to 8 SW devices can be cascaded via expansion bus without extra logic
 • Full duplex mode transfer
 • Less Bus overhead
 • Automatic flow control
■ Complete status report to a simple LED interface
■ Suitable for low cost Switch market to replace Hub
■ 0.35
m process, 3.3V with 5V tolerant I/O
■ 208-pin PQFP package