Features • Wireless Interface Following the IEEE 802.11b Standard • Wireless LAN MAC Unit with ARM7TDMI® RISC Processor • Integrated 128-byte Transmit and 128-byte Receive FIFOs for Wireless MAC Layer Functions • 16-bit PCMCIA Bus Interface • Glueless SRAM Interface for All MAC Operations, Supporting up to 1M Byte of External Memory • Integrated 6K x 32-bit Internal SRAM, Used for Fast Program Code Execution and Temporary Storage of Data • Glueless Flash Memory Interface, Supporting up to 1M Byte of Nonvolatile Memory for • • • • • • • • • Permanent Storage of Program Code Enciphering/Deciphering of Wireless Data On-the-fly by the Implementation of the Encryption/Decryption Code Ensures Maximum Privacy of Data The Integrated Physical Attachment Interface (PAI) Fully Supports Direct-sequence Spread Spectrum and Frequency-hopping Spread Spectrum (2 Mbps) Physical-layer Interfaces The WLAN and Inter-networking Functions can be Changed and Updated Easily to New Requirements Since They are Implemented in Microcode Supports 11 Mbps Rates with Automatic Fallback to 5.5, 2 and 1 Mbps 144-lead TQFP Package Low-voltage 3.3V Operation Internal ROM Contains Hardwired CIS Information for Automatic Configuration when Card is Inserted in the PCMCIA Slot or Reads Custom CIS Information from SPI Memory Offers SPI interface and 3 GPIO Pins AT76C502A Offers the Option to Download the Whole Code from SPI DataFlash® or an Option to Eliminate Flash by Downloading the Program from the Mass Storage Device 11-megabit WLAN Media Access Controller (MAC) AT76C502A Summary Block Diagram PCMCIA Interface Internal Memory ARM7TDMI Common Memory Interface Controller External Memory Interface Timers Decoder/ Arbiter/ Bridge Interrupt Controller Wireless Physical Attachment Interface (PAI) WEP 1948DS–WLAN–09/03 Note: This is a summary document. A complete document is available under NDA. For more information, please contact your local Atmel sales office. Description Fast VirtualNet™ (AT76C502A) is a single-chip controller that provides all processing 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 conforming 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 physical 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® operating mode. However, a 16-bit instruction subset is also available in Thumb® mode. Thumb mode can be selected to exploit full processor power with limited external memory resources. Note that ARM7TDMI operating mode can be changed at run time with negligible overhead. Functional Diagram ASB PCMCI Controller random WEP TxFIFO RxFIFO ASB Data Bus MUX Common Memory Interface Controller Wireless Physical Attachment Interface (WPAI) control Local Memory I/F Memory Interface Controller 2 ASB WLAN ASB ASB Internal Memory #1 Wireless PHY Signals ASB ASB Control Path 22 Bits Wireless LAN ARM Core (WLANARM) Decoder/Arbiter/ Bridge APB Timers, Interrupt Controller WLAN MAC Unit AT76C502A 1948DS–WLAN–09/03 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. Blvd. Colorado Springs, CO 80906, USA Tel: 1(719) 576-3300 Fax: 1(719) 540-1759 Biometrics/Imaging/Hi-Rel MPU/ High Speed Converters/RF Datacom Avenue de Rochepleine BP 123 38521 Saint-Egreve Cedex, France Tel: (33) 4-76-58-30-00 Fax: (33) 4-76-58-34-80 Zone Industrielle 13106 Rousset Cedex, France Tel: (33) 4-42-53-60-00 Fax: (33) 4-42-53-60-01 1150 East Cheyenne Mtn. Blvd. Colorado Springs, CO 80906, USA Tel: 1(719) 576-3300 Fax: 1(719) 540-1759 Scottish Enterprise Technology Park Maxwell Building East Kilbride G75 0QR, Scotland Tel: (44) 1355-803-000 Fax: (44) 1355-242-743 Literature Requests www.atmel.com/literature Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard warranty which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel’s products are not authorized for use as critical components in life support devices or systems. © Atmel Corporation 2003. All rights reserved. Atmel® and combinations thereof, and DataFlash ® are the registered trademarks of Atmel Corporation or its subsidiaries. ARM7TDMI ®, ARM ®, ARM7 ®, and Thumb ® are the registered trademarks of ARM, Ltd.; AMBA ™ is the trademark of ARM, Ltd. Other terms and product names may be the trademarks of others. Printed on recycled paper. 1948DS–WLAN–09/03