AT76C502A

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



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). AT76C502 A 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 AT76C502A 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.