This example application acts as a Paho MQTT Client to connect to Secured MQTT Broker (Ali Cloud) and publishes and subscribes to data on subtopics.

This application demonstrates how a user can use the Paho MQTT Client to connect to a Secured MQTT Broker (Ali Cloud). The application shall come up in AP Provisioing mode, and user will need to configure the Wi-Fi credentials for the Home AP. The default application will try to establish MQTT TLS connection with “ProductKey”.iot-as-mqtt.cn-shanghai.aliyuncs.com and publishes message to a topic every 30 sec.

To download or clone this application from Github, go to the top level of the repository

To build the application, refer to the following table and open the project using its IDE.

• Connect the Debug USB port on the board to the computer using a micro USB cable
• On the GPIO Header (J207), connect U1RX (PIN 13) and U1TX (PIN 23) to TX and RX pin of any USB to UART converter
• Home AP (Wi-Fi Access Point with internet connection)

1. Open the project

2. Currently MQTT Service is configured to run a MQTT Client in Secured mode to connect to 'PRODUCT-KEY'.iot-as-mqtt.cn-shanghai.aliyuncs.com on the mqtt secured port (1883). In case the user wants to change this config, please make the changes in the C Macro EXAMPLE_PRODUCT_KEY/EXAMPLE_DEVICE_NAME/EXAMPLE_DEVICE_SECRET in the app.c, and MQTT server address at psMqttCfg->sBrokerConfig.brokerName

3. The WIFI credentials can be changed at source code at configuration.h It also can be changed after programmed. Provision the device using the following CLI Command "wifiprov set 0 1 "GEN" 0 1 3 "DEMO_AP" "password"" for Home AP with SSID DEMO_AP, and password as 'password'. More details on the CLI command can be found here.
   

4. Another way to change the WIFI credentials was through the Harmony 3 Configurator
   

5. Build and program the generated code into the hardware using its IDE

6. Open the Terminal application (Ex.:Tera term) on the computer

7. Connect to the "USB to UART" COM port and configure the serial settings as follows:

   • Baud : 115200
   • Data : 8 Bits
   • Parity : None
   • Stop : 1 Bit
   • Flow Control : None

8. The Board will connect to Home AP and then as per the default MQTT Service configuration, it shall connect to 'PRODUCT-KEY'.iot-as-mqtt.cn-shanghai.aliyuncs.com and publish messages on the topic '/sys/PRODUC-TKEY/DEVICE-NAME/thing/event/property/post' periodically every 30 sec. It also subscribes to topic '/sys/PRODUC-TKEY/DEVICE-NAME/thing/service/property/set'
   

9. Login into the Ali IoTStudio, test the device connection.

10. Press button SW1 will trigger publish a MQTT package to update the button state. And the button state can be viewed at Ali IoTStudio Dashboard
    

11. Send YellowLEDStatus to the Device will turn on the Green LED on the board.

12. Now you are all set. On the next, you can launch Harmony3 configurator to add a new feature. The project was based on paho_mqtt_client example, add ATECC608 secure element driver and several PINs for the PIC32MZ W1 Curiosity Board. Note: The secured tcp connection may require the user to modify WolfSSL component settings in MHC depending on the security settings of the site/ server he is trying to access.