An application for the STMicroelectronics STM32L4 Discovery Kit IoT Node using ARM Mbed OS to connect to AWS IoT cloud. In parts it is inspired by the example AWS IoT from Mbed OS device using the Wifi and sensor example from Team ST. Although specifically built for the IOT01A-model, it should be compatible with the Non-US IOT01B-model.
I built the program as I was unable to connect the STM32L4 to the AWS IoT cloud with any existing examples or libraries. I provide it on an AS IS basis for anyone that wants to get ahead faster with the STM32, ARM Mbed and AWS IoT. Therefore the intended user of this program should bring some basic C/C++ knowledge.
In order to run the program on your STM32L475, you need to configure and compile it. I will explain the process using the Mbed online compiler for which you need to create a free account on os.mbed.com. Further you need to have an AWS account to create AWS IoT things.
Make sure you are logged in to your mbed.com account. You can easily import the program into the mbed online compiler using the following link: Import the program into the compiler. You will afterwards see the program and it's code components, just as on GitHub.
You will need the certificate and the private key that AWS IoT created for your thing as well as the endpoint that can be found in the Settings section of AWS IoT. These information need to be inserted into the corresponding sections inside the configuration file MQTT_server_setting.h.
const char MQTT_SERVER_HOST_NAME[] = "INSERT_THING_ENDPOINT_HERE.iot.eu-central-1.amazonaws.com";
const char* SSL_CLIENT_CERT_PEM = "-----BEGIN CERTIFICATE-----\n"
"INSERT YOUR THING CERTIFICATE HERE!\n"
"-----END CERTIFICATE-----\n";
const char* SSL_CLIENT_PRIVATE_KEY_PEM = "-----BEGIN RSA PRIVATE KEY-----\n"
"INSERT YOUR THING PRIVATE KEY HERE!\n"
"-----END RSA PRIVATE KEY-----\n";
Once changed the application is ready to compile. The compiler will provide you a bin-file that you can easily copy onto your STM32L4. The program outputs several debug information, so in case it fails you will be able to track the issue through the console.