• IEEE 802.11b-compliant Wireless Standard
• Wireless LAN MAC Unit with ARM7TDMI™ RISC Processor
• Integrated 128-byte Transmit and 128-byte Receive FIFOs, for Wireless MAC Layer
• Delivers Standard Wireless Networking to Any Host that Supports a Full-speed
(12 Mbps) USB Interface
• Glueless SRAM Interface for All MAC Operations, Supporting up to 1M Byte of External
• 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 Bytes of Nonvolatile Memory
for Permanent Storage of Program Code
• Wired Equivalent Privacy (WEP) in Hardware Supporting 64-bit and 128-bit Encryption
• The Integrated Physical Attachment Interface (PAI) Fully Supports Direct-sequence
Spread Spectrum and Frequency-hopping Spread Spectrum Physical-layer Interfaces
• The WLAN and Inter-networking Functions can be Changed and Updated Easily to New
Requirements Since They are Implemented in Micro Code
Supports 11 Mbps Data Rate with Automatic Fallback to 5.5, 2 and 1 Mbps
128-lead, 14 x 14 mm TQFP Package
Low-voltage Operation (3.3V)
Internal ROM Contains Hardwired USB Control Software for Automatic Configuration
when Card is Inserted in the USB Slot
• Device Firmware Upgrade is also Included in the Internal ROM for Downloading
Firmware into Internal SRAM
• Offers SPI Interface and Five GPIO Pins
• AT76C503A Offers the Option to Download the Whole Code from SPI Flash
Universal Serial
Bus 11-megabit
WLAN Media
Block Diagram
External Memory
Internal Memory
Wireless Physical
Attachment Interface
USB Interface
Internal/External Memory
Interface Controller
Rev. 1949CS–WLAN–06/02
Note: This is a summary document. A complete document is
available under NDA. For more information, please contact your
local Atmel sales office.
AT76C503A 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). AT76C503A provides a glueless interface conforming to 12-Mbit
Universal Serial Bus (USB) specification and can control a variety of wireless physical
The AT76C503A chip contains a USB interface, a MAC control unit, and a PAI. The PAI
supports 5.5- and 11-Mbit WLAN physical interfaces and the IEEE 802.11 (1 or 2 Mbps)
direct-sequence spread spectrum and frequency-hopping spread spectrum 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.
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© Atmel Corporation 2002.
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
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