Sending SMS Command (AT+CMGR) error on PIC18F452

[softlab]

Dear sir,
I used PIC18F452 to communicate with SIMCOMM300 Gsm Modem. I done everything OK. It works fine for all AT Commands except "AT+CMGR". This command also processed successfully but not come out from the loop. I tried my level best to correct the issue. But still I didn't find success. Anyone can provide help to correct the issue.

IDE: MPLAB v8.63
Compiler: MPLAB C18v3.37
PIC18F452
SIMCOMM300 GSM Modem

GSM Modem Initialized with:

ATE0 - OK         //echo-off
AT+CMGF = 1  - OK  // SMS Text mode
AT+CLIP = 1  - OK // To extract incoming phone number

Serial Port settings (as mentioned in sample program provided along with mplab c18 compiler).

OpenUSART (USART_TX_INT_OFF &    //Set and Open Serial Port
             USART_RX_INT_ON &
             USART_ASYNCH_MODE &
             USART_EIGHT_BIT &
             USART_CONT_RX &
             USART_BRGH_HIGH, 25);

If Message received "+CMTI : SM", <msg number>, it process and split the msg number and displayed correctly.

if(strcmp(strBuff, SMS_CMTI) == 0){
    *strBuff = 0;
            
    split(gsmOutput_s);
    *gsmOutput_s = 0;
    //memset(gsmOutput_s, 0, sizeof(gsmOutput_s));
    while(BusyUSART());
    putrsUSART((const far rom char*)"AT+CMGR=");
    putsUSART(SMS_SPLIT[1].SMS_Rec); //received message number
    while(BusyUSART());
    putcUSART(0x0D);
}

Read SMS also works fine. Reading Msg and split the incoming SMS Phone number and displayed correctly. Here the compiler hangs. It didn't process further. I have to restart the PIC.

if(strcmp(strBuff, SMS_CMGR) == 0){
    strBuff = 0;
    split(gsmOutput_s);
        
    pch = strstr(SMS_SPLIT[1].SMS_Rec, AdminPhNum);
           memset(strBuff_IncomingPhNum, 0, sizeof(strBuff_IncomingPhNum));
    strncpy(strBuff_IncomingPhNum, pch, 10);
            
    WriteCmdXLCD(CLR_LCD); 
    while(BusyXLCD()); 
    WriteCmdXLCD(HOME_LCD); 
    while(BusyXLCD()); 
            
    if (strcmp(strBuff_IncomingPhNum, AdminPhNum) == 0){
          putrsXLCD("Admin SMS");
    }
    else{
                
          putrsXLCD("Anonymous SMS");
    }
}

The split function is:

void split(char input[]){
 
    char *output[7];
    int loop;
    
    output[0] = strtokpgmram(input, (const far rom char*)","); 
    
    if(output[0]==NULL) 
    { 
        return;
    } 
    
    for(loop=1;loop<strlen(input);loop++) 
    { 
    
        output[loop]=strtokpgmram(NULL, (const far rom char*)","); 
        if(output[loop]==NULL) 
        break; 
    } 
    
    for(loop=0;loop<strlen(input);loop++) 
    { 
        if(output[loop]==NULL) 
        break; 
            
        strcpy(SMS_SPLIT[loop].SMS_Rec, output[loop]);
        
    } 
}

All others AT Commands work fine. It correctly parse the incoming Phone number if call received and interrupts also works fine.

I am facing problem only in "AT+CMGR" Command. Really I was so tired in finding the bug. Please help me.