AN3972

Application firmware description

Doc ID 022161 Rev 1

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Application firmware description

The firmware has been developed over the FreeRTOS operating system in order to simplify

the integration of the different application parts. Figure 4 shows the firmware architecture.

Figure 4.

Firmware architecture

The firmware includes a common hardware dependent layer which mainly includes the

STM32 standard library; over this layer the libraries and the application tasks are grouped in

two sections: one for the ZigBee part and the other for the TCP/IP part. The FreeRTOS

allows the correct execution of these tasks and their interaction.

3.1

ZigBee section

3.1.1

ZigBee libraries

The ZigBee libraries, which are independent from the OS, are part of the firmware package

of the STEVAL-IHP001V3 board and are fully documented; please refer to www.st.com.

3.1.2

ZigBee application layer

The application is based on the same principle as the typical “sink - sensors” scenario

supporting a “many-to-one” protocol, where there are several sensors (which in this case

are the smartplugs) that periodically send data to a concentrator, which in this case is also

the network coordinator, and is implemented by the STM3210C-EVAL.

The application layer is implemented by the task prvApplicationTask which is implemented

inside the “main.c” file. It calls the function emberTick, which includes the functions for the

ZigBee stack finite state machine evolution, and the function applicationTick, which

implements the ZigBee section of the application layer.

The application maintains a list of the smartplugs joined to the HAN; a smartplug is removed

from this list when it isn't heard from for a specified time and it is added when the

concentrator receive a “select-sink” message from it; this message is managed in

handleSensorSelectSink called by the callback function ezspIncomingMessageHandler. At