ASIX ELECTRONICS CORPORATION

9

AX88772A/AX88172A

Low-pin-count

USB 2.0 to 10/100M Fast Ethernet Controller

1.0 Introduction

1.1 General Description

The AX88772A/AX88172A Low-pin-count USB 2.0 to 10/100M Fast Ethernet controller is a high performance and

highly integrated ASIC which enables low cost, small form factor, and simple plug-and-play Fast Ethernet network

connection capability for desktops, notebook PC’s, Ultra-Mobile PC’s, docking stations, game consoles, digital-home

appliances, and any embedded system using a standard USB port.

The AX88772A/AX88172A features a USB interface to communicate with a USB Host Controller and is compliant with

USB specification V1.1 and V2.0. The AX88772A/AX88172A implements a 10/100Mbps Ethernet LAN function based

on IEEE802.3, and IEEE802.3u standards with 24KB of embedded SRAM for packet buffering. The

AX88772A/AX88172A integrates an on-chip 10/100Mbps Ethernet PHY to simplify system design.

The AX88172A provides an optional External Media Interface (EMI) for external PHY or external MAC for different

application purposes. The EMI can be a media-independent interface (MII) for implementing 100BASE-FX Ethernet or

HomePNA functions. The EMI can also be a Reverse-MII or Reverse Reduced-MII (Reverse-RMII) for glueless

MAC-to-MAC connections to any MCU with Ethernet MAC MII or RMII interface. In addition, the EMI can be

configured to Dual-PHY mode allowing AX88172A to act as an Ethernet PHY or USB 2.0 PHY for external MAC device

that needs Ethernet and USB interfaces in their system applications. The optional serial interface such as I2C, SPI, and

UART are provided as a control channel from the USB Host Controller to communicate with the external MCU chip.

The AX88772A/AX88172A needs 12MHz clock for USB operation and 25Mhz clock for Fast Ethernet operation. The

AX88772A is housed in the 64-pin LQFP and the AX88172A is housed in the 80-pin TQFP RoHS compliant package.

1.2 Block Diagram

Figure 7

: AX88772A/AX88172A Block Diagram

DP/DM

RXIP/RXIN

TXOP/TXON

GPIO_2~0

MAC

Core

Memory

Arbiter

USB to

Ethernet

Bridge

USB Core and Interfaces

STA

SEEPROM

Loader I/F

EECS

EECK

EEDIO

24KB SRAM

General Purpose

I/O

10/100M

Ethernet

PHY

Serial I/F

Controller:

UART/I2C/SPI

SI_3~0

AX88172A only

External Media Interface

MII /

Reverse-MII /

Reverse-RMII

MDC / MDIO

3.3 to 1.8V

Regulator

PLL Clock

Generators

Power-On-Reset

& Reset Gen.

RESET_N

XTL25P, XTL25N

XTL12P, XTL12N

PHY/MAC

mode Bridge