GSM interfacing with PIC18F4550

[Alamgir]

I am using PIC18F4550 for interfacing with GSM SIM 900. i have cheked it via hyperterminal at baud rate of  9600 and the gsm work perfectly, but when now at the controller it dosn’t give the expected results. The c code written in mp lab is given. please help me with this, why isn’t it working.

 

#include<p18f4550.h>
#include<delays.h>

# pragma config WDT=OFF
# pragma config LVP=OFF
# pragma config FOSC=HS
# pragma config IESO=OFF
# pragma config MCLRE=ON
# pragma config PBADEN=OFF

unsigned char value=0;
int i=0, k=0,j=0;

unsigned char *at_cmd=”AT”;
unsigned char *sms_format=”AT+CMGF=1″;
unsigned char *sms_write=”AT+CMGS=”03006464297″”;
unsigned char *sms=”Hello”;
unsigned char enter=0x0D;
unsigned char *data;

#define FREQ 11059200
#define baud 9600
#define spbrg_value (((FREQ/64)/baud)-1)
unsigned char rx_data(void);

void tx_data(unsigned char serial_data)    ;
void gsm_cmd(unsigned char *);
int check(unsigned char *);

void main()
{

    TRISB=0;
    LATB=0;
   
 
    TRISC=0xC0;
   
 

   
    
    
    //BAUDCONbits.WUE=1;

    TXSTAbits.SYNC=0;
    BAUDCONbits.BRG16=0;
    SPBRG=spbrg_value;            // Fill SPBRG register to set the baud rate

    
    INTCONbits.GIE=1;                // Enable Global interrupt
    INTCONbits.PEIE=1;                // Enable Peripheral interrupt
    
    

     RCSTAbits.SPEN=1;                // To activate serial port (Tx and Rx pins)
    PIE1bits.RCIE=1;                // Enable Reception interrupt
    RCSTAbits.RX9=0;

    RCSTAbits.CREN=1;                // Activate Reception
    

   
    PIE1bits.TXIE=1;
    PIE1bits.RCIE=1;
    TXSTAbits.TX9=0;
    TXSTAbits.TXEN=1;                // Activate Transmissiom
    RCSTAbits.RX9=1;
                     

while (1)
{
        {
PORTBbits.RB0=1;
            gsm_cmd(at_cmd);
            Delay10TCYx(500);
           i=0;
while(i<2)
{
data=rx_data();
i++;
}            
if (check(data))
      {  
        PORTBbits.RB1=1;
           
            gsm_cmd(sms_format);
            Delay10TCYx(500);
          i=0;
while(i<2)
{
data=rx_data();
i++;
}           
if (check(data))
{
      PORTBbits.RB2=1;
      gsm_cmd(sms_write);
            Delay10TCYx(500);
        

PORTBbits.RB3=1;            
 gsm_cmd(sms);
             
            tx_data(0x1A);
            Delay10TCYx(500);

}
}
}
}
}

unsigned char rx_data(void)
{
    while(PIR1bits.RCIF==0);                            // Wait until RCIF gets low
    return RCREG;                                   // Retrieve data from reception register
}

void tx_data(unsigned char serial_data)        // Transmit data function
{
    TXREG=serial_data;
    while(PIR1bits.TXIF==0);
}

void gsm_cmd(unsigned char *string)
{
i=0,j=0;
    while(string!=’’)
    {
        tx_data(string);    
        i++;
    }
    tx_data(enter);    
}

int check(unsigned char *string)
{
int i=0;
if(string==’O’)
{
i++;
if(string==’K’)
{return 1;
}
else
return 0;
}
else
return 0;

}

[AJISH ALFRED]

Hi Alamgir,

Connect your controller to the hyperterminal and make the code running. Obsere whether your controller generates the same commands there.

[Nidhin]

Hi…

          

         I build this program. it is succesfully build in my mplab c complier.   I dont know what are the issues u facing. can you upload the circuit diagram of this project.??

[Author]

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