Gsm interfacing with atmega16

[ANTI_HACKER]

Hello everyone!
I am working on GSM sim900D interfacing with Atmega16. Initially I made the circuit using MAX232 on breadboard. Then i connected it to my PC using a serial port. I tested AT commands, the commands worked perfectly on hyper terminal and i was able to send sms using hyperterminal. Then I tested it on Proteus and it was working there perfectly too. I am using codevision avr as the compiler. GSM work on 9600baud but the problem is that in compiler i have to keep the baud rate4800(clock = 1MHz) and at proteus COMPIM(physical baud=9600 & virtual baud=4800) only then it works when i run it on hardware(breadboard) it doesn't work as i have set the baud to 4800. I dont know how to set the baud for hardware. I tried 9600baud for hardware in compiler but it doesnot send sms at all. Kindly tell what should i do?
Thanks in advance

 

[Jestin_cubetech]

//atmega 16  UART  
//////////////////UART CONFIG/////////////////
SREG|=0X80;
DDRD =0XFE;
UCSRB=0x98;    //8BIT //1 STOP BIT //NO PARITY //RXCIE ENABLE
UCSRC=0x86;    //ASYNC  
UBRRH=0x0;  
UBRRL=0x47;    //BDRT 9600     Xtal  11.0592Mhz

 

[sherazi]

As u are using 1MHz clock , use 4800 baud as i use... In Proteus Set physical and virtual both to 4800. but before doing that change the baud-rate of sim900D using the command AT+IPR=4800 <CR>

The problem you are facing is because the SIM900d is set to 9600 , and micro controller set to 4800. IN Proteus you are converting that 4800 to 9600 ,,, but in your circuit you are not doing it . using 1MHz means u have to choose 4800.


another solution is change your clock to 8Mhz and baudrate to 9600 on Microcontroller.

 

[madhusuthanan]

replace the crystal to 11.0592MHz & calculate the 9600 baud rate load that value. then check it.

 

[ANTI_HACKER]

I tried changing the baud to 4800 with 1MHz clock but still its not working on breadboard
Now I'm checking by changing crystal to 8MHz *fingers crossed*

- - - Updated - - -

I tried(in simulation proteus) by changing baud to 9600 and clock to 8MHz & 11.0592MHz but none of it work. It should first work in simulation then on breadboard what should i do now?

- - - Updated - - -

Please help what should i do to get over it?

 

[Jestin_cubetech]

check your osc configuration bits

 

[madhusuthanan]

gs is communication is at 9600 baud rate.

- - - Updated - - -

sorry gsm is communication is at 9600 baud rate.

 

[electronicsbasecom]

Maybe this previous post will help you: https://www.edaboard.com/threads/228304/
I use it for my project: http://www.electronics-base.com/ind...via-gprs-siemens-es75-modem-using-at-commands

Greetings...

 

[ANTI_HACKER]

still not working
can anyone tell me exactly which crystal to use with what baud?

 

[madhusuthanan]

crystal is value is 11.0592MHz & its baud rate is 9600. load value for this baud rate calculated value is fine.

 

[sherazi]

the problem seemed to be pretty straight forward ...

please upload your schematic and hex file along with source code , so that I can check and correct it for you.

 

[ANTI_HACKER]

This is my code here please check it and guide me through this..
I have communicated through 4800
but I am having problem with 9600 baud
kindly tell me the clock value and and the baud values of the terminal and com port in proteus
please.. i am waiting

#include <mega16.h>
#include <delay.h>

#define F_CPU 8000000UL
#define USART_BAUDRATE 9600
#define BAUD_PRESCALE (((F_CPU / (USART_BAUDRATE * 16UL))) - 1)



#define rs PORTD.2 // defining rs pin to be PORTC.O
#define rw PORTD.3 //defining rs pin to be PORTC.1
#define en PORTD.4 //defining en pin to be PORCT.2

int j,msg_rcd,count,NUMBER;
unsigned char data,message_no,;
long i,z,speed_mph;
unsigned char rec_rfid[20],speed_kph[15],speed_knots[15],validation,utc_time[15], UTC[15],lati_value[15], LATITUDE[15],lati_dir, longi_value[15], LONGITUDE[15],longi_dir ;



 void init_USART(void)
{
    UCSRA = 0x00; //control register initialization
    UCSRB = 0x18; //enable transmitter and Rx   and rx interrupt
    UCSRC = 0x86; //async, no parity, 1 stop bit,
    
    UBRRL = BAUD_PRESCALE; // Load lower 8-bits of the baud rate value into the low byte of the UBRR register
    UBRRH = (BAUD_PRESCALE >> 8); // Load upper 8-bits of the baud rate value into the high byte of the UBRR register
    
}






void USART_Rx() 
{ 
    while((UCSRA & 0x80)==0x00); //wait for RXC flag       
    data = UDR;
}




void USART_Tx(char DATA) 
{ 
    while((UCSRA & 0x20)==0x00); //wait for UDRE flag
    UDR = DATA; //load data to UDR for transmission
     
}







  
void main()
{

    DDRA=0XFF;
    DDRD.2=1;
    DDRD.3=1;
    DDRD.4=1;

    
 
    init_USART();
    
    
    
    
    while(1)
    {
        USART_Tx('A');
        USART_Tx('T');
        USART_Tx('\r'); 
        delay_ms(1500);
    }
    
     

}

 

[sherazi]

the first thing to do is to change the clock of ur microcontroller in proteus F_CPU wont chnage it , do it in object proprties

also if your device is not set to AUTO BAUD you have to either set it to AUTO BAUD or Fixed baud. I guess it is auto baud so you dont need to worry , IN case the above step doest help check the baud rate and set it to auto baud.

 

[peterkj93@gmail.com]

sir,could you please send me that circuit in Proteus,for our project.our diagram is not working