#include <avr/io.h>
        #include <util/delay.h>
		#define F_CPU 1000000

        void USART_Init(void)					
        {

            UBRRL = 25;				// sets 1Mhz, 2400bps, .2% error
            UCSRB = (1<<RXEN)|(1<<TXEN);		// Enable receiver and transmitter
            UCSRC = (1<<URSEL)|(1<<USBS)|(3<<UCSZ0);// Set frame format: 8data, 2stop bit

        }


        void USART_Transmit( char data )
        {
        					
            while ( !( UCSRA & (1<<UDRE)) )		// Wait for empty transmit buffer
            ;
            UDR = data;				// Put data into buffer, sends the data
        }


        void Check_If_Done(char *str)
        {
           
            while(*str) 
               
                USART_Transmit(*str++);
            
        	
        }


        void SPI_MasterInit(void)			//Initialize Atmega8 as master
        {
        						 
            DDRB = (1<<DDB5)|(1<<DDB3)|(1<<DDB2);	// Set MOSI,SCK and SS\ output, all others input
        						
            SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);	// Enable SPI, Master, set clock rate fck/16
        }


        void SPI_MasterTransmit(char cData)		//Transmit data on the SPI interface	
        {
        	
            SPDR = cData;				// Start transmission 
        	
            while(!(SPSR & (1<<SPIF)))		// Wait for transmission complete 
            ;
        }


		void TransmitUDPacket(char *str)
		{

    char sync[] = "SYNC TX";

    char pkt[] = "PACKET TX";

    //CSn(0);    
  //  while(bit_is_set(PINB,4)){}
     SPI_MasterTransmit(0x36);     //idle mode
	 SPI_MasterTransmit(0x3A);     //rx flush

	  _delay_ms(50);

	 SPI_MasterTransmit(0x33);	   // scal strobe
    


    SPI_MasterTransmit(0x35);
    SPI_MasterTransmit(0x7F);        //write TXFIFO

    while(*str)
        SPI_MasterTransmit(*str++);


		SPI_MasterTransmit(0x3B);

   /* while(bit_is_clear(PINB,0))
    {
    //PORTC=0x01; //set PC0 high 
    //delay_ms(100);

    }
    Check_If_Done(sync);            //print SYNC TX when sync transmission gets completed

    while(bit_is_set(PINB,0)) 
    {
    //PORTC=0x00;
    }
    Check_If_Done(pkt);            //print PACKET TX when packet transmission gets completed
     //*/ 

    //CSn(1);

}


        void SPI_MasterReceive(void)
        {
            char RegValue, i;
            char ReceivedValue[11];
			unsigned char c;
			float RSSI_dec;
			float RSSI_dBm;
			char trans[3];
			trans[0]= 'h';
			trans[1]= 'i';
			trans[2]= '\0';

            char on[]="ON";
            char off[]="OFF";

            SPI_MasterTransmit(0x3D);

            RegValue = SPDR;
        	
            USART_Transmit(RegValue);

            for(i=0; i<11; i++)
            {

                SPI_MasterTransmit(0x3D);

                ReceivedValue[i] = SPDR;

            }
			     	
            if((ReceivedValue[0]=='a') & (ReceivedValue[1]=='b') & (ReceivedValue[2]=='c') & (ReceivedValue[3]=='d') & (ReceivedValue[4]=='e') & (ReceivedValue[5]=='f') & (ReceivedValue[6]=='g') & (ReceivedValue[7]=='h'))
            {
                if((ReceivedValue[8]=='y'))
			   
                {
                   PORTC|=((1<<PC0)|(1<<PC1)|(1<<PC2));
				   Check_If_Done(ReceivedValue);
                        _delay_ms(250);
					TransmitUDPacket(trans);
					Check_If_Done(trans);
                    PORTC&=~(1<<PC0);
                    
					
				}
				/*c=ReceivedValue[9];
				RSSI_dec=(float)c;

				if(RSSI_dec>= 128) 
				RSSI_dBm =((RSSI_dec - 256)/2 - 74);
				else 
				RSSI_dBm =((RSSI_dec)/2 - 74);
				 
				 if(RSSI_dBm<(-107))
				{
				PORTC|=(1<<PC0);
				 _delay_ms(1000);
                PORTC&=~(1<<PC0);
					}


			/*	if (RSSI_dec<190)
				{
				PORTC|=(1<<PC0);
				 _delay_ms(1000);
                PORTC&=~(1<<PC0);
				}

				

                /*else if((ReceivedValue[8]=='n'))
                {
                    PORTC&=~((1<<PC1)|(1<<PC2));
                    PORTC|=(1<<PC0);
                        _delay_ms(1000);
                    PORTC&=~(1<<PC0);
                    Check_If_Done(off);*/
                } 
            }
        


        void CSn(int i)					//Toggle CSn
        {
            if(i==1)
            PORTB|=0x04;
            else
            PORTB&=0xFB;
        }


        void Write_RegConfig(char addr,char value)	//send register value of a particular register
        {
            SPI_MasterTransmit(addr);
            SPI_MasterTransmit(value);	
        }

        	
        void Full_RegConfig(void)			//for full register configuration using BURST access
        {
            CSn(0);
            while(bit_is_set(PINB,4)){}

            SPI_MasterTransmit(0x3E);		//address for patable access
            SPI_MasterTransmit(0xC0);		//patable for PA power control settings

            SPI_MasterTransmit(0x40);		//burst transfer 1st address

            SPI_MasterTransmit(0x29);		//data written at register 0x00
            SPI_MasterTransmit(0x2E);		//data written at register 0x01
            SPI_MasterTransmit(0x06);		//data written at register 0x02
            SPI_MasterTransmit(0x47);		//data written at register 0x03
            SPI_MasterTransmit(0xD3);		//data written at register 0x04
            SPI_MasterTransmit(0x91);		//data written at register 0x05
            SPI_MasterTransmit(0x3D);		//data written at register 0x06
            SPI_MasterTransmit(0x04);		//data written at register 0x07 EARLIER 04
            SPI_MasterTransmit(0x01);		//data written at register 0x08 EARLIER 05
            SPI_MasterTransmit(0x00);		//data written at register 0x09
            SPI_MasterTransmit(0x00);		//data written at register 0x0A
            SPI_MasterTransmit(0x06);		//data written at register 0x0B
            SPI_MasterTransmit(0x00);		//data written at register 0x0C
            SPI_MasterTransmit(0x10);		//data written at register 0x0D
            SPI_MasterTransmit(0x09);		//data written at register 0x0E EARLIER A7 866
            SPI_MasterTransmit(0x7B);		//data written at register 0x0F EARLIER 62 866
            SPI_MasterTransmit(0xF5);		//data written at register 0x10	CA
            SPI_MasterTransmit(0x75);		//data written at register 0x11	EARLIER 83 866
            SPI_MasterTransmit(0x03);		//data written at register 0x12	13
            SPI_MasterTransmit(0x22);		//data written at register 0x13
            SPI_MasterTransmit(0xE5);		//data written at register 0x14	EARLIER F8 866
            SPI_MasterTransmit(0x14);		//data written at register 0x15 EARLIER 15 866
            SPI_MasterTransmit(0x07);		//data written at register 0x16
            SPI_MasterTransmit(0x30);		//data written at register 0x17
            SPI_MasterTransmit(0x18);		//data written at register 0x18
            SPI_MasterTransmit(0x16);		//data written at register 0x19
            SPI_MasterTransmit(0x6C);		//data written at register 0x1A
            SPI_MasterTransmit(0x03);		//data written at register 0x1B
            SPI_MasterTransmit(0x40);		//data written at register 0x1C
            SPI_MasterTransmit(0x91);		//data written at register 0x1D
            SPI_MasterTransmit(0x87);		//data written at register 0x1E
            SPI_MasterTransmit(0x6B);		//data written at register 0x1F
            SPI_MasterTransmit(0xF8);		//data written at register 0x20
            SPI_MasterTransmit(0x56);		//data written at register 0x21
            SPI_MasterTransmit(0x10);		//data written at register 0x22
            SPI_MasterTransmit(0xE9);		//data written at register 0x23
            SPI_MasterTransmit(0x2A);		//data written at register 0x24
            SPI_MasterTransmit(0x00);		//data written at register 0x25
            SPI_MasterTransmit(0x1F);		//data written at register 0x26
            SPI_MasterTransmit(0x41);		//data written at register 0x27
            SPI_MasterTransmit(0x00);		//data written at register 0x28
            SPI_MasterTransmit(0x59);		//data written at register 0x29
            SPI_MasterTransmit(0x7F);		//data written at register 0x2A
            SPI_MasterTransmit(0x3F);		//data written at register 0x2B
            SPI_MasterTransmit(0x81);		//data written at register 0x2C
            SPI_MasterTransmit(0x35);		//data written at register 0x2D
            SPI_MasterTransmit(0x09);		//data written at register 0x2E

            CSn(1);
        	
        }


        void SimpleReceive(void)
        {
			//char RSSI_value;

            char sync[] = "SYNC TX";

            char pkt[] = "PACKET TX";

            while(1)
            {

            CSn(0);	
            //while(bit_is_set(PINB,4)){}
			 _delay_ms(100);
            SPI_MasterTransmit(0x34);		//SRX STROBE

        	
            while(bit_is_clear(PINB,0)){}
            Check_If_Done(sync);

            while(bit_is_set(PINB,0)){}
            Check_If_Done(pkt);

        				
            SPI_MasterTransmit(0xFF);		//BURST READ RXFIFO

            SPI_MasterReceive();
			
			//SPI_MasterTransmit(0xF4);
			//RSSI_value=SPDR;
			//USART_Transmit(RSSI_value);
					
        	
            CSn(1);

            }	
        	
        }

        	
        int main()
        {

            char done[] = "Done";

            char start[] = "Start";

            DDRC =(1<<DDC2)|(1<<DDC1)|(1<<DDC0);	// 0 for Buzzer, 1 for LED, 2 for Relay
            PORTC =(1<<PC2)|(0<<PC1)|(0<<PC0);

            SPI_MasterInit();

            USART_Init();


            Check_If_Done(start);

            Full_RegConfig();			//CC1101 configured

            Check_If_Done(done);

            SimpleReceive();
        	
            return 0;	
        }