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Interfacing Tiva C Launchpad with SIM900 GSM Modem

Other Parts Discussed in Thread: ENERGIA, MAX232

Hi, I currently own Tiva C Series Launchpad (TM4C123GXL) and SIMCOM SIM900 GSM Modem

(http://www.sainsmart.com/arduino/arduino-shields/wireless-shield/simcom-sim900-gprs-gsm-quad-band-module-development-board-for-avr-mcu-arm.html)

I am trying to use Energia to write code into Tiva C launchpad and send data to SIM900 via TxD/RxD

and make a call or send sms to certain number.

My questions are,

1. Do I need MAX232 to connect RxD and TxD between Tiva C launchpad and SIM 900?

2. As of Hardware connection, do I just connect (USB->Tiva C) =>RxD & TxD ->(Power Supply->SIM900) like that?

    Do I need to be aware of additional hardware connections between these two?

3. As for Arduino, there are lot of library header files that could use call or sms functions, is there any library

    I could use for Tiva C Launchpad in Energia for writing code?

   So far, all I could get started off is just

   

void setup() {               
2   
3    Serial.begin(9600);
4    pinMode(RED_LED, OUTPUT);
5 }
6  
7 void loop()
8 {
9    {
10      Serial.print("THANKS FOR WATCHING\n");
11      delay(100);
12      digitalWrite(RED_LED, HIGH);   // set the LED on
13      delay(500);              // wait for a second
14    }
15      digitalWrite(RED_LED, LOW);    // set the LED off
16      delay(500);
17       
18     
19 }

   Can I get further help with writing code for GSM Modem? Thank you so much :)

  • Hi Sukhyun,

         

    Sukhyun Hong said:
    1. Do I need MAX232 to connect RxD and TxD between Tiva C launchpad and SIM 900?

         Most probably yes, the SIMCOM SIM900 has an RS232 port. Search the internet for similar projects of interfacing SIMCOM SIM900 to microcontroller to get an idea.

    Sukhyun Hong said:

    2. As of Hardware connection, do I just connect (USB->Tiva C) =>RxD & TxD ->(Power Supply->SIM900) like that?

        Do I need to be aware of additional hardware connections between these two?

        I am not sure what you are trying to say. Much better to post a block diagram of your intended connections here.

    Sukhyun Hong said:

    3. As for Arduino, there are lot of library header files that could use call or sms functions, is there any library

        I could use for Tiva C Launchpad in Energia for writing code?

        I don't know of any Tivaware library that supports SMS. But, you can modify the uart_echo example to send AT commands to you SIMCOM SIM900 GSM Modem.

        Have you tried to communicate with your SIMCOM SIM900 GSM Modem by connecting the RS232 port to your PC?

    -kel

  • Hello all,

    I tried using uart_echo example to interface sim900 with tiva Launchpad  but I am facing very unique issue.

    My tiva  launchpad continuously strt sending at command and it does not stop. But if i don't connect gsm It sends only once on uart. If anybody could help on similar issue.

  • hi Mitesh. Did you manage to send AT-Commands to through the UART? I'm trying to do the same thing.