[AVR] How to pass the content of SDcard to VS1003 ?

 void VsSineTest(){
        unsigned char *p;
		unsigned int i;
		//p = HelloMP3;
	    /* Reset MP3 chip */
	   /* Pull xRESET low -> hardware reset */
	    VS1003B_XRESET_L(); 
		_delay_ms(100);            /* 100 ms delay */

	    /* Send dummy SPI byte to initialize SPI bus of Atmel microcontroller */
	    VS1003B_WriteByte(0xFF);
		
	    /* Un-reset MP3 chip */
	    VS1003B_XCS_H();
		/* Pull xCS high    */
	    /* Pull xDCS high   */
	    VS1003B_XDCS_H();
		 /* Pull xRESET high */
	    VS1003B_XRESET_H();
		_delay_ms(100);            /* 100 ms delay     */

	    /* VS10xx Application Notes, chapter 4.8 ---------------------------------*/
	    /* As an example, let's write value 0x0820 to register 00 byte by byte    */
	    VS1003B_XCS_L();
		 /* Pull XCS low, now SPI writes go to SCI port     */
	    VS1003B_WriteCMD(00,0x0820);
		VS1003B_WriteCMD(SCI_VOL,0x0000); //max volume
	
		 /* Send SPI Byte, then wait for byte to be sent.   */
	     /* 0x02 was WRITE command, 0x00 is register number */
	     /* This byte goes to MSB                           */
	     /* ..and this is LSB. (0x20=Allow Test Mode)       */
	    VS1003B_Delay();
		 /* Wait until Atmel MCU signals SPI write complete */
	    VS1003B_XCS_H();
		usart_pstr("WAITING FOR DREQ ! \n");
		/* Pull XCS high, now SPI writes don't go to SCI port. */
        loop_until_bit_is_set(VS1003B_PIN,VS1003B_DREQ);
        
	    if (bit_is_set(VS1003B_PIN,VS1003B_DREQ))
		  {
	       usart_pstr("\n DREQ = 1 \n \n");
		  }else
		  {
		   usart_pstr("\n DREQ = 0 \n \n"); 	  
		  }
	    /* pull XDCS low, now SPI writes go to SDI port    */

		VS1003B_XDCS_L();
		/* Send a Sine Test Header to Data port*/
		/*
		p=readFile(READ,"test.mp3");
		while (p <= &p[sizeof(p)-1])
		{
			VS1003B_WriteByte(pgm_read_byte(p++));
		}
		*/
		
		//read_sdcard();
		//readFile(READ,"test.mp3");
		
		
		//while (p <= &p[sizeof(p)-1])
		//{
		//	VS1003B_WriteByte(p++);
		//}
		
		while (p <= &HelloMP3[sizeof(HelloMP3)-1])
		{
			VS1003B_WriteByte(pgm_read_byte(p++));
		}
        
		/*
		        
		VS1003B_WriteByte(0x53);
		VS1003B_WriteByte(0xef);
		VS1003B_WriteByte(0x6e);
		VS1003B_WriteByte(0x44);
		VS1003B_WriteByte(0x00);
		VS1003B_WriteByte(0x00);
		VS1003B_WriteByte(0x00);
		VS1003B_WriteByte(0x00);
	    */
		      /* - This is a special VLSI Solution test header - */
	          /* - that starts a sine sound. It's good for     - */
	          /* - testing your code and the chip. */
	    
		VS1003B_Delay();
	    
	    VS1003B_XDCS_H();
	    _delay_ms(500);           /* 500 ms delay */

	    /* Stop the sine test sound */
		 VS1003B_XDCS_L();
	    	/*	
		VS1003B_WriteByte(0x45);
		VS1003B_WriteByte(0x78);
		VS1003B_WriteByte(0x69);
		VS1003B_WriteByte(0x74);
		VS1003B_WriteByte(0x00);
		VS1003B_WriteByte(0x00);
		VS1003B_WriteByte(0x00);
		VS1003B_WriteByte(0x00);
        */
		
	    //SPIWait();
		VS1003B_Delay();

	    //Mp3DeselectData();
        VS1003B_XDCS_H(); 
	    _delay_ms(500);            /* 500 ms delay */
		
		usart_pstr("Sine wave test 's stoped, change to SPI High! \n");
		
		VS1003B_XDCS_L(); // Pull XDCS low
		
		 
		 if (bit_is_set(VS1003B_PIN,VS1003B_DREQ))
		 {
			 usart_pstr("\n DREQ = 1 \n \n");
		 }else
		 {
			 usart_pstr("\n DREQ = 0 \n \n");
		 }
        
		for (i=0; i<2048; i++)
		{
			//while (bit_is_clear(VS1003B_PIN,VS1003B_DREQ)); // wait here until DREQ is high again
			
			VS1003B_WriteByte(0);
		}
		VS1003B_Delay(0xffff); // Wait until SPI transfer is completed
		//VS1003B_XDCS_H(); // Pull XDCS high
		_delay_ms(500);
		usart_pstr("VS1003 AND ATMEGA128 SAYING HELLO! \n \n" );
		
		
    }
	
	void read_sdcard()
	{
		unsigned char option, error, data[512], FAT32_active,f;
		unsigned int i;
		unsigned char fileName[13];
		unsigned char *p;
		 
		 

		
		TX_NEWLINE;
		TX_NEWLINE;
		usart_pstr("*********************************************");
		TX_NEWLINE;
		usart_pstr("    Riko is doing card Testing..  ");
		TX_NEWLINE;
		usart_pstr("*********************************************");
		TX_NEWLINE;

		cardType = 0;
		
		for (i=0; i<10; i++)
		{
			error = SD_init();
			if(!error) break;
		}

		if(error)
		{
			if(error == 1) usart_pstr("SD card not detected..");
			if(error == 2) usart_pstr("Card Initialization failed..");

			while(1);  //wait here forever if error in SD init
		}
		
		
		switch (cardType)
		{
			case 1:usart_pstr("Standard Capacity Card (Ver 1.x) Detected!");TX_NEWLINE;
			break;
			case 2:usart_pstr("High Capacity Card Detected!");TX_NEWLINE;
			break;
			case 3:usart_pstr("Standard Capacity Card (Ver 2.x) Detected!");TX_NEWLINE;
			break;
			default:usart_pstr("Unknown SD Card Detected!");
			break;
		}
		
		//SPI_HIGH_SPEED;	//SCK - 4 MHz
		_delay_ms(1);   //some delay


		FAT32_active = 1;
		error = getBootSectorData (); //read boot sector and keep necessary data in global variables
		if(error)
		{
			TX_NEWLINE;
			usart_pstr("FAT32 not found!");  //FAT32 incompatible drive
			FAT32_active = 0;
		}
           else
		   {
			   TX_NEWLINE;
			   usart_pstr("FAT32  found!");  //FAT32 incompatible drive
               _delay_ms(1000);
		   }
		   
          TX_NEWLINE;
		  //start to send the file to VS1003 begin
		            //readFile( READ, "test.mp3"); 
		            readFile( READ, "test.txt");
					
					
					//f=readFile( READ, "test.txt");
          				
    	  TX_NEWLINE;
  }