Anas Dalintakam
Published © GPL3+

MQTT tutorial for Azure sphere MT3620

A tutorial for Azure sphere MT3620 MQTT implementation

IntermediateProtip3 hours1,502
MQTT tutorial for Azure sphere MT3620

Things used in this project

Hardware components

Azure Sphere MT3620 Starter Kit
Avnet Azure Sphere MT3620 Starter Kit
×1

Software apps and online services

MQTT
MQTT

Story

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Code

main.c

C/C++
main code used to send data to mqtt and blink user led
/* Copyright (c) Microsoft Corporation. All rights reserved.
Licensed under the MIT License. */
// This sample C application for Azure Sphere demonstrates how to use a UART (serial port).
// The sample opens a UART with a baud rate of 115200. Pressing a button causes characters
// to be sent from the device over the UART; data received by the device from the UART is echoed to
// the Visual Studio Output Window.
//
// It uses the API for the following Azure Sphere application libraries:
// - UART (serial port)
// - GPIO (digital input for button)
// - log (messages shown in Visual Studio's Device Output window during debugging)
// - eventloop (system invokes handlers for timer events)
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
// applibs_versions.h defines the API struct versions to use for applibs APIs.
#include "applibs_versions.h"
//#include <applibs/uart.h>
#include <applibs/gpio.h>
#include <applibs/log.h>
//#include <applibs/eventloop.h>
#include "mqtt_utilities.h"
#include "common.h"
// By default, this sample targets hardware that follows the MT3620 Reference
// Development Board (RDB) specification, such as the MT3620 Dev Kit from
// Seeed Studio.
//
// To target different hardware, you'll need to update CMakeLists.txt. See
// https://github.com/Azure/azure-sphere-samples/tree/master/Hardware for more details.
//
// This #include imports the sample_hardware abstraction from that hardware definition.
#include <hw/sample_hardware.h>
//#include "eventloop_timer_utilities.h"
//MQTT Variable
#define MQTT_PUBLISH_PERIOD 500000000
//static EventLoopTimer* publishMQTTMsgTimer = NULL;
static char* mqttConf_topic = "AZURE";
static char* mqttConf_brokerIp = "192.168.43.59";
//MQTT Variable
//#define UART_SEND_PERIOD 5
//static EventLoopTimer* sendUartTimer = NULL;
//const size_t receiveBufferSize = 20;
// File descriptors - initialized to invalid value
//static int gpioButtonFd = -1;
//static int uartFd = -1;
//EventLoop *eventLoop = NULL;
//EventRegistration* uartEventReg = NULL;
//EventLoopTimer *buttonPollTimer = NULL;
// State variables
//static GPIO_Value_Type buttonState = GPIO_Value_High;
//const char* engineRPMCmd = "010C\r";
//const char* engineTempCmd = "0105\r";
//const char* engineFuelCmd = "012F\r";
//static int engineRPM;
//static int engineTemp;
//static int engineFuel;
//static char rxData[33];
//static char rxIndex = 0;
//static char Data[20];
//static void TerminationHandler(int signalNumber);
//static void SendUartMessage(int uartFd, const char *dataToSend);
//static void ButtonTimerEventHandler(EventLoopTimer *timer);
//static ExitCode InitPeripheralsAndHandlers(void);
//static void CloseFdAndPrintError(int fd, const char *fdName);
//static void ClosePeripheralsAndHandlers(void);
//mqtt test code
int test_mqtt()
{
Log_Debug("Im in\n");
int res = MQTTInit(mqttConf_brokerIp, "1883", mqttConf_topic);
Log_Debug(res);
Log_Debug("done init\n");
//MQTTPublish(mqttConf_topic, "{\"engineTemp\":\"67.0\",\"engineRpm\":\"32.0\",\"fuel\":\"51.0\"}");
MQTTPublish(mqttConf_topic, "Wiring It my way");
//  while (1)
//  {
// }
//Log_Debug("done publish\n");
}
/// <summary>
///     Main entry point for this application.
/// </summary>
int main(void)
//int main(int argc, char *argv[])
{//test_mqtt();
/*  Log_Debug("UART application starting.\n");
//  test_mqtt();
exitCode = InitPeripheralsAndHandlers();
// Use event loop to wait for events and trigger handlers, until an error or SIGTERM happens
while (exitCode == ExitCode_Success) {
EventLoop_Run_Result result = EventLoop_Run(eventLoop, -1, true);
// Continue if interrupted by signal, e.g. due to breakpoint being set.
if (result == EventLoop_Run_Failed && errno != EINTR) {
exitCode = ExitCode_Main_EventLoopFail;
}
}
ClosePeripheralsAndHandlers();
Log_Debug("Application exiting.\n");
// return exitCode;*/
int fd = GPIO_OpenAsOutput(SAMPLE_LED, GPIO_OutputMode_PushPull, GPIO_Value_High);
if (fd < 0) {
Log_Debug(
"Error opening GPIO: %s (%d). Check that app_manifest.json includes the GPIO used.\n",
strerror(errno), errno);
// return ExitCode_Main_Led;
}
const struct timespec sleepTime = {.tv_sec = 1, .tv_nsec = 0};
while (true) {
test_mqtt();
GPIO_SetValue(fd, GPIO_Value_Low);
nanosleep(&sleepTime, NULL);
GPIO_SetValue(fd, GPIO_Value_High);
nanosleep(&sleepTime, NULL);
}
}

app_manifest.json

JSON
set ip address and gpio
{
  "SchemaVersion": 1,
  "Name" : "UART_HighLevelApp",
  "ComponentId" : "4f2d9823-dbbd-4740-a7dd-198c32ba34fe",
  "EntryPoint": "/bin/app",
  "CmdArgs": [],
  "Capabilities": {
    "AllowedConnections": [ "192.168.43.59"],
    "Gpio": [ "$SAMPLE_LED" ],
   

  },
  "ApplicationType": "Default"
}

CMakeSettings.json

JSON
{
  "environments": [
    {
      "environment": "AzureSphere"
    }
  ],
  "configurations": [
    {
      "name": "ARM-Debug",
      "generator": "Ninja",
      "configurationType": "Debug",
      "inheritEnvironments": [
        "AzureSphere"
      ],
      "buildRoot": "${projectDir}\\out\\${name}",
      "installRoot": "${projectDir}\\install\\${name}",
      "cmakeToolchain": "${env.AzureSphereDefaultSDKDir}CMakeFiles\\AzureSphereToolchain.cmake",
      "buildCommandArgs": "-v",
      "ctestCommandArgs": "",
      "variables": [
        {
          "name": "AZURE_SPHERE_TARGET_API_SET",
          "value": "latest-lts"
        }
      ]
    },
    {
      "name": "ARM-Release",
      "generator": "Ninja",
      "configurationType": "Release",
      "inheritEnvironments": [
        "AzureSphere"
      ],
      "buildRoot": "${projectDir}\\out\\${name}",
      "installRoot": "${projectDir}\\install\\${name}",
      "cmakeToolchain": "${env.AzureSphereDefaultSDKDir}CMakeFiles\\AzureSphereToolchain.cmake",
      "buildCommandArgs": "-v",
      "ctestCommandArgs": "",
      "variables": [
        {
          "name": "AZURE_SPHERE_TARGET_API_SET",
          "value": "5"
        }
      ]
    }
  ]
}

referred repo

i modified codes using this project

Credits

Anas Dalintakam

Anas Dalintakam

13 projects • 34 followers
Electronics and communication engineer-IoT researcher-DIY electronics hobbyist-blogger-hackster-maker

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  • Avnet
  • Internet of Things
  • Microsoft
  • MQTT