ACTE UK > Technologies > Wireless LAN 802.11

 

Wireless LAN / 802.11 Technology

 

Wireless LAN (WLAN) uses a radio technology working in the free-to-use, world wide available 2.4 GHz and 5GHz ISM bands.

Several Wireless-LAN standards have been defined by the IEEE which refer to the frequency band and type of modulation to be used for meeting the specification and implying interoperability between different equipment and brands. Amongst other particulars the standards dictate maximum achievable data-rates between devices, and are referenced by an additional characters following the main 'IEEE 802.11' specification number - e.g. WLAN 802.11a,b,g for a device which supports the specification versions 'a', 'b' and 'g'.

Either TCP/IP or UDP protocol is used for data transfer, the same as for most internet and wired networking. Also like in wired networking a WLAN module has a permanent, unique MAC address and to take part in a WLAN network will have it's own, or be assigned an IP address for that network.

Our High Flying WLAN modules include all the software (TCP/IP stack and AT command interface) embedded into the module to simplify system design. This 'complete system-on-a-module' solution provides high performance and data-rates while offering an easy-to-implement interface via UART or USB.

Embedded low-cost Wireless LAN modules are now increasing being utilised in industrial and consumer markets for products as diverse as industrial automation to LED light bulbs.

The Wireless LAN modules page contains further information on our range of WLAN modules and specific design features for low-power and system integration.
 
 

Product Range

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Wireless LAN Module Features


With the inclusion of several new features, modules in each of the product families above have been used in many new applications. An brief explanation of some of these features follows.
 
Note that not all features are present on all modules, the product range overview and individual datasheets should be referred to for complete information. See the WLAN Modules page for further information.

 

Ultra-Low Power with Power management scheme

Low-Power device architecture is improved by using a custom developed IC to integrate several functions of the module, reducing cost and power consumption.

Depending upon the connectivity mode modules can activate an addition power saving scheme to reduce power further.

 

STA/AP/AP+STA modes

High Flying WLAN modules can act as either a ‘Station’ (i.e. Client of an Access Point) or as an Access Point for other WLAN devices to connect to.

If configured as a ‘Station’, e.g. provides WLAN access via the local UART, the devices can simultaneously act as an access point for another device (e.g smartphone / tablet) which can be used to configure parameters of the device without disturbing the original (Station) network setting. So a user can easily set up the modules parameters through WiFi and check the connection in real-time.

 

Friendly Web Configuration Page

Module with this feature have an inbuilt http server with 5 clearly laid out pages for device management. This greatly simplifies configuration for first time set-up and for future users with the AP+STA mode.

 

Ethernet Interface & Router/Bridge Mode

The high performance modules feature an Ethernet 10/100 PHY interface. Connections can be implemented as either a low-cost (transformer-less) AC-coupled to other Ethernet PHY modules or by adding a transformer and RJ45 connector to Cat-5 cabling.

When the Ethernet interface is implemented and has been enabled it is possible to define the module to act as a router or bridge depending up the access point or client modes of the WLAN

 

Palmodic Signal

This is an output signal which can indicate the module has finished normal boot up, and thereafter that the module is fully operational with active connections.

In transparent mode the UART interface is designated for data-transfer. To save changing modes this 0.5Hz square wave indicates all is OK whilst no data is being transferred.

 

GPIO / PWM control and monitoring

Monitoring and control of the module GPIO and PWM output is possible over the network by specific AT commands. It is possible to reduce the workload and power consumption for the host processor or to wake it over the network.

 

SDK for custom features:

Based upon the Keil MDK environment allows the user to create custom features inside the module such as:

  • Adding a user AT command function
  • Mapping a GPIO (inc. PWM, ADC) to a function
  • Modify communication & GPIO pin mapping
  • Control GPIO & comms interface pins

An example might be to create an AT command to send a HTTP request to a server and print the response to the serial port.

Depending upon the module flash memory size (1MB / 2MB) between 400 and 512K can be available for custom ‘SDK’ applications.