原标题：Freescale TWR-WIFI-AR4100低功耗2.4GHz无线连接方案

　　freescale公司的TWR-WIFI-AR4100是802.11n Wi-Fi超低功耗模块,采用Tower System可使物联网具有802.11n Wi-Fi 连接性,工作频率2.4GHz,网络标准包括802.11b, 802.11g和802.11n,模块集成了MAC/BB/RF/PA/LNA,硬件加密有WEP,WPA/WPA2,WAPI SPI通信接口.该模块能和Tower System的其它MCU和外设模块一起使用.本文介绍了AR4100主要技术指标,方框图和TWR-WIFI-AR4100模块主要特性,方框图,电路图和材料清单.

　　TWR-WIFI-AR4100: Tower System 802.11n Wi-Fi Module

　　Do you need an ultra-low power, easy wireless solution? The TWR-WIFI-AR4100 peripheral module enables the Internet of Things with 802.11n Wi-Fi connectivity using the Freescale Tower System. This fully FCC & CE-certified Atheros "System-in-Package" module comes with MQX software and enables you to quickly go from the lab to production with the same Wi-Fi hardware module.

　　The on-board Atheros silicon features easy to use wireless for the whole home and pre-certification will save you time and money getting your product to market. This peripheral module is designed to be combined and used with other microcontroller and peripheral modules in the Tower System.

　　TWR-WIFI-AR4100模块主要特性:

　　Low energy and low system resource requirements

　　Integrated RF front end, RF shield, 32kHz sleep clock, and system clock

　　Best in class Rx sensitivity for superior throughput rate-over-range performance

　　Integrated high-power, high efficiency linearized Power Amplifier

　　Low Density Parity Check (LDPC) encoding for improved uplink robustness over range

　　Space ock Coding (STBC) for improved downlink robustness over range

　　Wi-Fi Protected Setup (WPS)

　　Wi-Fi Direct™ ready

　　Compatible with the Tower System, including MQX based driver support

　　SPI interface to Tower MCU modules

　　On-board SPI Flash for enabling minimal impact to MCU resources

　　Access to expansion GPIO and debug signals for advance development

　　The TWR-WIFI-AR4100 Module contains:

　　802.11n Wi-Fi board with Atheros "System-in-Package"

　　Quick Start Guide

　　The AR4100 is a small form-factor, single stream, 802.11 b/g/n Wi-Fi “System-in-Package” (SIP) solution. The AR4100 has been developed to support applications hosted by low-resource microcontrollers that send infrequent data packets over the network. Typically, these 802.11 applications will place a higher priority on system cost, power consumption, ease of use, and fast wake-up times as compared to high throughput. The AR4100 integrates all Wi-Fi functionality into a low-profile, 8.3mm x 9.2mm LGA package that can be easily mounted via low-cost PCB manufacturing flows. The device requires only a few external bypass capacitors and a connection to an antenna for a board level design. As an added cost reduction and convenience, the SIP module is pre-certified with the FCC and other major regulatory bodies.

　　The AR4100 employs the world’s lowest power consumption embedded architecture. It has been optimized for client applications in the home and enterprise that have lower data rates, and transmit or receive data on an infrequent basis. The AR4100 features standby current consumption as low as 5uA. Additional optimizations, including a reduced host driver footprint, allow easy integration with low-cost microcontrollers.

　　The AR4100 also includes Atheros’ industry leading high-efficiency, high-output EPA™ power amplifier with zero calibration and integrated LNAs. RF matching circuits, a reference crystal, and a T/R switch are also integrated, eliminating the need for an external RF components and thus enabling direct antenna connection. The end result is a device that is the best-in-class for ease of system design.

　　At the heart of the AR4100 is an ultra low-power radio architecture and proprietary power save technologies. This low-power architecture can enable multi-year battery life from AA cells. The AR4100 also includes an on-chip, high-efficiency PMU (power management unit) that enables a direct-connect to battery, eliminating the need for external regulators. An on-chip embedded CPU handles complete 802.11 b/g/n processing to minimize host processor loading.

　　AR4100主要技术指标:

　　图1.AR4100方框图

　　The Atheros Wi-Fi Tower Module (TWR-WIFI-AR4100) is a low-cost evaluation, demonstration and development board that features an ultra-low power 802.11n solution from Atheros.

　　The TWR-WIFI-AR4100 Wi-Fi Tower System module features the AR4100 solution from Atheros. The following is a brief summary of the TWR-WIFI-AR4100’s features:

　　The Atheros AR4100, an ultra-low power, single stream (1x1) IEEE 802.11n System-in-package featuring:

　　Low energy and Low system resource requirements

　　Simple low cost wireless system integration

　　Near zero RBOM

　　Integrated RF front end, RF shield, and clocks

　　Direct connect to a 50-ohm antenna

　　Integrated PMU for battery operation

　　Atheros world class leading 802.11n Wi-Fi:

　　Integrated high-power, high efficiency Power Amplifier

　　Low Density Parity Check (LDPC) encoding for improved uplink robustness over range

　　Space Time Block Coding (STBC) for improved downlink robustness over range

　　Wi-Fi Protected Setup (WPS)

　　Wi-Fi Direct™ready

　　Compatible with the Tower System, including MQX based driver support

　　SPI interface to Tower MCU modules

　　On-board SPI Flash for enabling minimal impact to MCU resources

　　图2. TWR-WIFI-AR4100外形图

　　图3.TWR-WIFI-AR4100方框图

　　The TWR-WIFI-AR4100 module connects to the Freescale Tower platform using the SPI interface and can be easily integrated using the TCP/IP stack of the Freescale MQX system.

　　图4.TWR-WIFI-AR4100电路图(1)