ASIX ELECTRONICS CORPORATION

4

CONFIDENTIAL

AX88615P 5-Port 10/100Mb Switch Controller

PRELIMINARY

1.0 AX88615 Overview

1.1 General Description

The AX88615 is a 5-ports 10/100 Mbps Ethernet switch with MII PHY or RMII PHY. A low cost Fast Ethernet switch

can be implemented by using the AX88615 and low cost 64Kx32 SSRAM .

Data received from the MAC interface is stored in the external memory. All ports support multiple MAC addresses. The

switch provides a look-up table for 8K MAC addresses with two 64Kx32 SSRAMs. The AX88615 provides three frame

forwarding mode: store-and-forward mode, safe cut-through (fragment free) mode and dynamic-select-mode (auto). The

dynamic-select-mode means the switch selects optimizes mode for forwarding packages automatically according to

Network quality.

During transmission, the data is obtained from the buffer memory and routed to the destination port. For half-duplex

operation, the MAC control will back off and retransmit in accordance to the IEEE802.3 CSMA/CD if collision occurs.

The AX88615 provides two flow control methods. For half-duplex operation, an optional jamming based flow control is

available to avoid loss of data. This is also well known as back pressure. In the full-duplex mode, AX88615 utilizes

IEEE802.3X as the flow control mechanism.

1.2 AX88615 Block Diagram:

Fig - 1 AX88615 Block Diagram

P0 10/100 MAC

P1 10/100 MAC

P2 10/100 MAC

P3 10/100 MAC

P4 10/100 MAC

High Speed

Switch Fabric

Routing /Learning

Controller

Buffer Manager

Buffer Memory

Interface

LED Interface

MII / RMII

PHY

MII / RMII

PHY

MII / RMII

PHY

MII / RMII

PHY

MII / RMII

PHY

64K*32 SSRAM