2

AT76C502A

1948DS–WLAN–0

9/03

Description

Fast VirtualNet

and functionality needed for the MAC protocol of wireless LANs (focusing on, but not

limited to the IEEE 802.11b standard). AT76C502A provides a glueless interface con-

forming to PC Card 95 and can control a variety of physical interfaces.

The AT76C502A chip contains a PCMCIA bus interface, a MAC control unit and a phys-

ical attachment interface (PAI). The PAI supports direct-sequence spread spectrum and

frequency-hopping spread spectrum (2 Mbps) physical interfaces, providing flexibility to

end users.

The ARM7TDMI core supports two alternative instruction sets. Powerful 32-bit code can

be executed by the processor in ARM

subset is also available in Thumb

processor power with limited external memory resources. Note that ARM7TDMI operat-

ing mode can be changed at run time with negligible overhead.

Functional Diagram

Wireless Physical

Attachment

Interface (WPAI)

Control Path

WLAN ASB

WEP

control

random

ASB Data Bus

PCMCI Controller

Wireless

PHY

Signals

22 Bits

APB

Timers,

Interrupt

Controller

Decoder/Arbiter/

Bridge

Wireless LAN

ARM Core

(WLANARM)

Local

Memory I/F

Internal

Memory #1

Common

Memory

Interface

Controller

Memory Interface

Controller

WLAN MAC Unit