MQTT Library on Microcontroller

Question

I want use MQtt Protocol as Messing protocol. I want to port the Mqtt Library on Microcontroller TMS470(Texas Instrument) with CCS Compiler. Since I am new to this Protocol, Can

Answer 1

I have similar problem, I'm using STM32F405 and GPRS module( Quectell M95 ). I can't receive MQTT package correctly. As my experience, With PAHO embedded C library , I can publish a test Message to iot.eclipse.org.

Benjamin MQTT with CC3200 example is very good to understand concept. Watch the video tutorial.

http://blog.benjamin-cabe.com/2014/08/26/mqtt-on-the-ti-cc3200-launchpad-thanks-to-paho-embedded-client

As I understand, PAHO embedded C library serilaze MQTT package and you need to implant transport method to library. ( Send /Recive / Connect / Disconnect )

This is my transport_sendPacketBuffer() function, It just puts buffer to gprs module. Don't use printf. cause, MQTT package can be contain 0x00 , or any type of data. "buflen" is calculated by library.

int transport_sendPacketBuffer(int out, char* buf, int buflen)
{
     int i=0;
     for(i=0;i<=buflen;i++){
          put(buf[i]); // Put One char to GPRS modem .
     }
}

Before you transport_data You need to connect socket with AT Command, There are several methods to connect. It depends on your GSM module AT+Command / TCP documantation ( Transparent / Multiple Connect ) If you have an library for your GSM module it will be help much too.

This is simple Quectel M95 TCP socket connection command, AT+QIOPEN

int  CONNECT_SERVER_SOC (char *ip,int soc ){

    char bf[128];
    sprintf(bf,"AT+QIOPEN=\"TCP\",\"%s\",%d\r\n",ip,soc); // ip= "198.41.30.241", port:1883
                                                          // iot.eclipse.org
    printf("%s",bf);
}

If you can handle recive message I will glad to hear it.