Datasheet

6. WLAN Subsystem

The WLAN subsystem is composed of the Media Access Controller (MAC) and the Physical Layer (PHY).

The following two subsections describe the MAC and PHY in detail.

6.1 MAC

6.1.1 Description

The ATWINC15x0-MR210xB MAC is designed to operate at low power while providing high data

throughput. The IEEE 802.11 MAC functions are implemented with a combination of dedicated datapath

engines, hardwired control logic, and a low-power, high-efficiency microprocessor. The combination of

dedicated logic with a programmable processor provides optimal power efficiency and real-time response

while providing the flexibility to accommodate evolving standards and future feature enhancements.

Dedicated datapath engines are used to implement datapath functions with heavy computational

requirements. For example, an FCS engine checks the CRC of the transmitting and receiving packets,

and a cipher engine performs all the required encryption and decryption operations for the WEP, WPA-

TKIP, and WPA2 CCMP-AES.

Control functions which have real-time requirements are implemented using hardwired control logic

modules. These logic modules offer real-time response while maintaining configurability via the

processor. Examples of hardwired control logic modules are the channel access control module

(implements EDCA/HCCA, Beacon TX control, interframe spacing, etc.), protocol timer module

(responsible for the Network Access Vector, back-off timing, timing synchronization function, and slot

management), MPDU handling module, aggregation/de-aggregation module, block ACK controller

(implements the protocol requirements for burst block communication), and TX/RX control FSMs

(coordinate data movement between PHY-MAC interface, cipher engine, and the DMA interface to the

TX/RX FIFOs).

The MAC functions implemented solely in software on the microprocessor have the following

characteristics:

• Functions with high memory requirements or complex data structures. Examples are association

table management and power save queuing.

• Functions with low computational load or without critical real-time requirements. Examples are

authentication and association.

• Functions which need flexibility and upgradeability. Examples are beacon frame processing and

QoS scheduling.

6.1.2 Features

The ATWINC15x0-MR210xB IEEE802.11 MAC supports the following functions:

• IEEE 802.11b/g/n

• IEEE 802.11e WMM QoS EDCA/PCF multiple access categories traffic scheduling

• Advanced IEEE 802.11n features:

– Transmission and reception of aggregated MPDUs (A-MPDU)

– Transmission and reception of aggregated MSDUs (A-MSDU)

– Immediate Block Acknowledgment

– Reduced Interframe Spacing (RIFS)

ATWINC15x0

WLAN Subsystem

Datasheet

DS70005304C-page 13