Temperature Sensor Example Application

Table of Contents

• SysConfig Notice
• Introduction
• Hardware Prerequisites
• Software Prerequisites
• Functional Description
  • Software Overview
  • Application Files
  • Example Application
• Configuration With SysConfig
• Usage
  • Buttons
  • Display
  • Setting up the Thread Network
  • Interfacing with the Example Application

Introduction

This document discusses how to use the Temperature Sensor Example Application and the different parts that compose it. Thermostat Example Application is a standalone CoAP server example running on Thread.

Some of the areas explored are:

• Setting up a network.

• Bringing up the device as a Minimum Thread Device (MTD).

• Initialization and use of the Constrained Application Protocol (CoAP) APIs.

Hardware Prerequisites

Device Reporting example

• 3 x CC13X2 /CC26X2 Wireless MCU LaunchPads

• 1 x BeagleBone Black.

• (optional) 1 x Sharp128 LCD boosterpack.

Basic CoAP usage

• 2 x CC13X2 /CC26X2 Wireless MCU LaunchPads

• (optional) 1 x Sharp128 LCD boosterpack.

Software Prerequisites

• Code Composer Studio (CCS) v10.0 or higher

Functional Description

Software Overview

This section describes software components and the corresponding source file.

Application Files

• tempsensor.[ch]: Contains the application's event loop, CoAP callback functions, device initialization function calls, and all temperature sensor specific logic.

• otstack.[ch]: OpenThread stack processing, instantiation and network parameters.

• task_config.h: This file contains the definitions of the RTOS task priorities and stack sizes.

• tiop_config.[ch]: Contains OpenThread stack configurations. If using a SysConfig-enabled project (see the Configuration with SysConfig section below), these files are generated and configured through the SysConfig GUI. If using a non-SysConfig project, the files are a part of the project and parameters can be directly modified.

• tiop_ui.[ch]: Contains functions and defines to enable Thread-specific functionality for the Common User Interface (CUI).

• tiop_app_defs.h: Contains application-specific configurations for CUI.

Example Application

This application provides an example implementation of a temperature sensor using the Thread wireless protocol and CoAP as the application layer protocol. The temperature sensor application is configured as a Minimal Thread Device (MTD) which supports CoAP commands to read the temperature. The temperature sensor example also includes basic reporting functionality to a known IPv6 address, in this case the thermostat example application.

Configuration With SysConfig

SysConfig is a GUI configuration tool that allows for TI driver and stack configurations. In order to configure projects using SysConfig, use the SysConfig-enabled version of the Thread examples located in <SDK_ROOT>/examples

To configure using SysConfig, import the SysConfig-enabled project into CCS. Double click the *.syscfg file from the CCS project explorer, where * is the name of the example project. The SysConfig GUI window will appear, where Thread stack and TI driver configurations can be adjusted. These settings will be reflected in the generated files tiop_config.[ch].

The example project comes with working default settings for SysConfig. It is not recommended to change the default driver settings, as any changes may impact the functionality of the example. The Thread stack settings may be changed as required for your use case.

One important note about TI-OpenThread SysConfig is how SysConfig settings and non-volatile storage settings are applied. If the LaunchPad non-volatile holds a valid Thread dataset, SysConfig settings will not be applied on boot. SysConfig settings are only applied when non-volatile storage does not hold a valid Thread dataset. To guarantee SysConfig settings are applied, perform a factory reset of the non-volatile storage, as described below.

Usage

This section describes how to set up and run the Temperature Sensor Example Application.

Buttons

• BTN-2 at boot: A factory reset of the non-volatile storage is performed. This must be pressed at the start of the OtStack_task function.

• BTN-2: Start the joining process. This may be pressed after the hold image appears on-screen.

Display

The temperature sensor events will be displayed through UART to a serial terminal emulator. To enable the serial terminal in CCS press Ctrl + Shift + Alt + T, select Serial Terminal under Choose terminal, select 115200 for Baud Rate and click OK. PuTTY may also be used as the serial terminal emulator. The serial interface implements a Common User Interface (CUI). More details are provided in the "Example Applications" section in the Thread docs of the SDK. Application-specific portions of CUI are described below.

Setting up the Thread Network

This section describes how to set up a Thread network. The application supports the ability to be commissioned into a Thread network. Commissioning may be bypassed by setting the TIOP_CONFIG_SET_NW_ID parameter to 1 in tiop_config.h and setting the network ID parameters there. This can also be done through SysConfig in the TI-OpenThread stack module, under the Network ID submodule. By setting the PAN ID to a valid, non-broadcast ID (not 0xFFFF), the device can be pre-commissioned to an existing network.

1. Set up a LaunchPad as a CLI FTD device by following the README files in the respective application folder.

2. Load and run the Temperature Sensor example on a second LaunchPad.

3. The Temperature Sensor will print out the device's EUI64 and the application's PSKd (pre-shared key device identifier) in CUI. If the device was already commissioned or bypassed as described above, skip to step 8.

   Device Info: [EUI64] 0x00124b000f6e6113  [PSKD] TMPSENS1
   

4. Start a commissioner on the CLI FTD by issuing the following command: commissioner start. It will display Done if it succeeds in becoming the active commissioner.

5. Add the Temperature Sensor LaunchPad device as a joiner device by providing the EUI64 and pskd (from step 3) as credentials to the commissioner: commissioner joiner add 00124b000f6e6113 TMPSENS1. It will display Done if it is successful in adding the joiner entry.

6. Now on the Temperature Sensor LaunchPad, press BTN-2 to start the joining process. The UART will print Joining Nwk ....

7. Once the joining process has successfully completed, the UART will print Joined Nwk. The green LED should turn on on the LaunchPad once it has joined the network.

8. Next we need to get the IPv6 address of the temperature sensor LaunchPad. The temperature sensor is a sleepy end device; we cannot discover the address using the realm-local all nodes multicast. Transmission of realm-local multicasts by parent routers is detailed in section 5.2.3.2 of the Thread 1.1.1 specification. It is necessary to use the Realm-Local All-Thread-Nodes multicast address. This address will have the form ff33:0040:<ML-PREFIX>::1, where <ML-PREFIX> is the 64 bit mesh-local prefix. This address may be discovered with the command ipmaddr. On the CLI, use the command ping ff33:0040:<ML-PREFIX>::1 to send an ICMP echo request to the realm-local all nodes multicast address. All devices on Thread network will respond with an ICMP echo response. You will see in the terminal a response like the one below.

   8 bytes from fdde:ad00:beef:0:0:ff:fe00:b401: icmp_seq=1 hlim=64 time=11ms
   

Running the example with reporting

The Temperature Sensor example has a basic reporting feature. When connected to a network with a Globally Unique Address, the temperature sensor will attempt to post the temperature it reads to the thermostat. To enable this feature you need to setup a Thread network with an NCP connected to a BeagleBone Black and a LaunchPad with the Thermostat Example. Consult the NCP example's README for information on setting up a BeagleBone Black based border router.

NOTE: This kind of static addressing is a hack of SLAAC. Proper discovery mechanisms are being explored.

Interfacing with the Temperature Sensor Example Application

The temperature sensor application hosts a simple CoAP server with one registered resource for the current temperature. This resource supports CoAP GET commands. Any device with scope of the temperature sensor's IPv6 address can send commands to the temperature sensor application.

Temperature Sensor Attribute URI:

• Temperature value: tempsensor/temperature

Open up the serial terminal to the cli_ftd application and also to the temperature sensor application.

Starting the CoAP client

In the CLI FTD serial terminal, execute coap start at the prompt to start the CoAP service. It will display the following message if it successful in starting the CoAP service. Coap service started: Done

Getting status from the Temperature Sensor

To get the temperature sensor's current temperature, execute the following command on the CLI FTD terminal.

coap get fd00:db7:0:0:0:ff:fe00:b401 tempsensor/temperature

NOTE: The IPv6 address will be different for your setup

The temperature sensor should respond, and the cli_ftd will print a message like the following.

Received coap response with payload: 3730

Converting the payload from hex to ascii we get 70 which is the temperature in degrees Fahrenheit.

This value is the same value displayed on sensor at the time of sending the response.

   APP Info: [Temperature] 70 [Poll Period] 2000

NOTE: The Poll Period field indicates how often the device polls its parent. This is used as both a keep-alive and a poll for any pending data.

Application-specific CUI

There are currently no application-specific actions for the temperature sensor.