How to interface GSM modem with PIC16F877A and send sms from PIC16F877A to GSM MODEM

/ LCD connection
sbit LCD_RS at RB2_bit;
sbit LCD_EN at RB3_bit;
sbit LCD_D4 at RB4_bit;
sbit LCD_D5 at RB5_bit;
sbit LCD_D6 at RB6_bit;
sbit LCD_D7 at RB7_bit;

sbit LCD_RS_Direction at TRISB2_bit;
sbit LCD_EN_Direction at TRISB3_bit;
sbit LCD_D4_Direction at TRISB4_bit;
sbit LCD_D5_Direction at TRISB5_bit;
sbit LCD_D6_Direction at TRISB6_bit;
sbit LCD_D7_Direction at TRISB7_bit;

 // Manchester module connections
sbit MANRXPIN at RC6_bit;
sbit MANRXPIN_Direction at TRISC6_bit;
sbit MANTXPIN at RC7_bit;
sbit MANTXPIN_Direction at TRISC7_bit;
// End Manchester module connections

//prototype
  //void pic_Send_SMS();
  //void Read_SMS(void);
  //void gsm_SMS_Init(void);
  void writeWarning();
  void writeNormal();
  void Move_Delay();
  //void delay(unsigned long ctr);
  void Man_send_init();
  //end of prototype
  
// Declaration start
char output[70] = " LOW OIL LEVEL T4 ILALA ";
unsigned int *counter, i;
char return_gsm[2];
char Gsm_Receive[50];
char Gsm_Msg[100];
unsigned int THRESHOLD = 0xCd;
unsigned int read_value = 0;
char index, character;
char *set[] = " LOW OIL LEVEL T4 ILALA ";
char *text1 = " !! WARNING !!";
char *text2 = " LOW OIL LEVEL ";
char *text3 = " T4 ILALA_EAST ";
char *text5 = " SAFE OPERATION ";
char *text4 = " TRANSFORMER AT ";
//char *COMError = " Initialization error";
char *sms = " LOW OIL LEVEL T4 ILALA_EAST ";
int change = 0;         //  change is 0 for  safe operation and 1 for unsafe operation
int ANSEL, ANSELH, C1ON_bit, C2ON_bit;
char USART_rd[] = "AT";
char USART_rd1[]= "AT+CMGF=1";
char USART_rd2[]= "AT+CMGR=1";
char USART_rd3[]= "AT+CMGS= 1";
// End of declaration part

void main()
{
  // pic16f877A

 ANSEL  = 0x02;              // Configure AN1 pin as analog
 ANSELH = 0;                 // Configure other AN pins as digital I/O
 C1ON_bit = 0;               // Disable comparators
 C2ON_bit = 0;

 TRISB = 0;                    // PORTB as output port
 TRISD = 0;                     // PORTD as output port
 TRISC = 0;                   //  PORTC as output port
 TRISA = 0X07;               // PORTA as the input/output 0000 0111
 UART1_Init(9615);              // Initialize Soft UART module at 9600 bps
 Move_Delay();                // Wait for UART module to stabilize
 Lcd_Init();                        // Initialize LCD connected to PORTB
 Lcd_Cmd(_LCD_CLEAR);              // clear Display
 Lcd_Cmd(_LCD_CURSOR_OFF);        // Turn cursor off
 Lcd_Out(1, 1, text4);             // "transformer at" text
 Lcd_Out(1, 1, text5);            // display safe operation on lcd

 do
   {
    read_value = ADC_Read(1);   // Get 10-bit results of AD conversion
    PORTD = read_value;         // Send lower 8 bits to PORTB

 if(read_value > THRESHOLD )                    // if true mean abnormal operation
   {
       if(change == 0)
       {
          writeWarning();                  // call function to display warning on lcd and send sms to GSM
          //gsm_SMS_Init();              // initialize gsm modem
           //pic_Send_SMS();                    //send an sms
           //Read_SMS();

          change = 1;
       }

   }
     else    // safe
   {
      if(change == 1)              // if the previous condition is exit i.e unsafe operation
      {

        writeNormal();         // call function to display safe operation on lcd
        change = 0;           // set to safe operation
      }
   }

  } while(1);
}

void writeWarning()
{
      Lcd_Init();
      Lcd_Cmd(_LCD_CLEAR);              // clear Display
      Lcd_Cmd(_LCD_CURSOR_OFF);        // Turn cursor off
      Lcd_Out(1,1,text1);
      Lcd_Out(2, 1, text2);                  // Print  text to LCD, first row
      Lcd_Out(3, 1, text3);                 // Print text1 to LCD 3rd row

}
void writeNormal()
{
   Lcd_Init();
   Lcd_Cmd(_LCD_CLEAR);              // clear Display
   Lcd_Cmd(_LCD_CURSOR_OFF);        // Turn cursor off
   Lcd_Out(1,1, text4 );             // text to display
   Lcd_Out(1, 1, text5);            // display normal operation on lcd


}

void Move_Delay()       // function used for text delay
{
  Delay_ms(500);       //  delay for half a second
}

void Read_SMS(void)
{
   pic_Send_SMS();         // send text
   UART1_Write_Text("AT+CGMM= 1");    // GET supported frequency band
   UART1_Write_Text("AT");    // send AT to the GSM
   //Move_Delay();               // Delay
   UART1_Write_Text("AT+CMGF=1 ");      // sms configuration  /SET TEXT MODE
   //Move_Delay();
   UART1_Write_Text("AT+CNMA= 1");    //ACKNOWLEDGE NEW SMS
   UART1_Write_Text("AT+CMGR= 1\n\r");
   UART1_Write_Text("AT+CGMR= 1\n\r");      // request revision identification
   //Move_Delay();
   UART1_Write_Text("AT+CPMS= output");    // store from the ram  (BM)
   UART1_Write_Text("AT+CMGL= 1");      //list message
   UART1_Write_Text("AT+CMGR= 1\n\r");      // Read message
   //Move_Delay();
   UART1_Write_Text("AT+CPMS= output");    // read from the ram  (BM)
   while (UART1_Data_Ready() == 0) ;
   for(i=0;i<=65;i++)
   {
     output[i]=UART1_Read();
   }
   
}
void pic_Send_SMS()
{
      do
      {
          //gsm_SMS_Init();
          //Read_SMS();                         //to read the sms in location 1
          UART1_Write_Text("AT+CSMS= 1");       // SMS AT command
          UART1_Write_Text("AT+CGMI= 1");       //gives manufacturer identification
          UART1_Write_Text("AT+CMGS= +0682006300");    //Write "AT+CMGS= 1"
          UART1_Write(0x0D);                 // mean (Enter)
          Move_Delay();                        // Delay
          UART1_Write_Text("AT+CMGW= 1");     // WRITE message
          UART1_Write_Text("AT+CMSS= 1");      //SEND MESSAGE
          //UART1_Write_Text("AT+CMGS= ");    //Write "AT+CMGS="
          UART1_Write(0x22);
          UART1_Write_Text("AT = +255682006300");   // Phone Number  SMS send to
          UART1_Write(0x22);
          UART1_Write(0x0D);            // mean (ENTER)
          UART1_Write_Text("\n\r");
          Move_Delay();                   // Delay
          UART1_Write_Text(output);       // Word to be sent
          UART1_Write(26);                     // send ctrl + Z
          Move_Delay();                      // Delay

      }
        while(1);

}