#include <avr/io.h>
  #include <inttypes.h>
  #include <avr/interrupt.h>
  #include "AT45DB161D_opcodes.h"

  #define Sampl_freq 44100
  #define F_CPU 20000000
 

   unsigned char df_BufferNum;
   unsigned char df_Read_BufferNum;
   unsigned int df_BufferIdx;
   unsigned int df_Read_BufferIdx;
   unsigned int df_PageAdr;
   unsigned int df_Read_PageAdr;
   unsigned char df_Read_END;
   unsigned char df_Stop_Write;

//----------
unsigned char spi_transfer(unsigned char mydata)
{
   unsigned char temp;
  
   USIDR  = mydata;
   mydata = 0x11;
   temp   = 0x13;

   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;
   USICR  = mydata;
   USICR  = temp;  

return (USIDR);
}
//----------
void Init(void)
{
  PORTB  = (1<<PB0)|(1<<PB1)|(1<<PB2)|(1<<PB3)|(0<<PB4);
  DDRB   = (0<<PB0)|(1<<PB1)|(1<<PB2)|(1<<PB3)|(1<<PB4);
  MCUSR  = 0;
  PLLCSR = 0b00000110;   /* Select PLL clock for TC1.ck */
  GTCCR  = 0b01000000;   /* Enable TC1.OCB as PWM out (L-ch) */
  TCCR1  = 0b01000001;   /* Start TC1 with TC1.OCA is enabled as PWM out (R-ch) */   

  TCCR0A = 0b00000010;   /* Enable TC0.ck = 2MHz as interval timer */
  TCCR0B = 0b00000010;
  TIMSK  = (1<<OCIE0A);
            
  OCR0A = (unsigned char)(F_CPU / 8 / Sampl_freq );
            
  asm("sei");

  df_Read_END=false;
  
  dataflash_CS_inactive();     //disable device
}
//----------
void dataflash_CS_inactive()
{
  PORTB = _BV(PB3);//digitalWrite(DF_SLAVESELECT,HIGH); //disable device
}
//----------
void dataflash_CS_active()
{
  PORTB = ~_BV(PB3);//digitalWrite(DF_SLAVESELECT,LOW); //enable device
}
//----------
unsigned char ReadStatus(void)
{
  unsigned char tmp;
  
  dataflash_CS_inactive();    // Reset dataflash command decoder
  dataflash_CS_active();    
 
  // Read status command
  spi_transfer(DF_STATUS_REGISTER_READ);
  tmp = spi_transfer(0x00);
  return(tmp&0x80);  // We only want to extract the READY/BUSY bit
}
//----------
void PageToBuffer(unsigned char BufferNum, unsigned int PageAdr)
{
  dataflash_CS_inactive();   
  dataflash_CS_active();  
  if (BufferNum==1)    
    spi_transfer(DF_TRANSFER_PAGE_TO_BUFFER_1);
  else
    spi_transfer(DF_TRANSFER_PAGE_TO_BUFFER_2);  
  spi_transfer((unsigned char)(PageAdr >> 6));   
  spi_transfer((unsigned char)(PageAdr << 2));   
  spi_transfer(0x00);   // don?t care bytes     

  dataflash_CS_inactive();   //initiate the transfer
  dataflash_CS_active();
  
  while(!ReadStatus());  //monitor the status register, wait until busy-flag is high
}
//----------
unsigned char BufferRead (unsigned char BufferNum, unsigned int IntPageAdr)
{
  unsigned char tmp;
  
  dataflash_CS_inactive();   // Reset dataflash command decoder
  dataflash_CS_active();
  
  if (BufferNum==1)   
    spi_transfer(DF_BUFFER_1_READ);
  else
    spi_transfer(DF_BUFFER_2_READ);
  spi_transfer(0x00);     //don't cares
  spi_transfer((unsigned char)(IntPageAdr>>8));  //upper part of internal buffer address
  spi_transfer((unsigned char)(IntPageAdr));  //lower part of internal buffer address
  spi_transfer(0x00);                            //don't cares
  tmp = spi_transfer(0x00);           //read data byte
  
  return (tmp);
}

//----------
void WaitReady()
{
  while(!ReadStatus());
}
//----------
void StartRead(int PageAdr)
{
  df_Read_BufferNum=1;
  df_Read_BufferIdx=0;
  df_Read_PageAdr=PageAdr;
  WaitReady();
  PageToBuffer(df_Read_BufferNum,df_Read_PageAdr);  // Write Memory page to buffer
  df_Read_PageAdr++;
}
//----------
unsigned char ReadByte()
{
  unsigned char result;
  
  WaitReady();
  result = BufferRead(df_Read_BufferNum,df_Read_BufferIdx);
  df_Read_BufferIdx++;
  if (df_Read_BufferIdx >= 512)  // End of buffer?
    {
    df_Read_BufferIdx=0;
    PageToBuffer(df_Read_BufferNum,df_Read_PageAdr);  // Write memory page to Buffer
    df_Read_PageAdr++;
    if (df_Read_PageAdr>=4096)  // If we reach the end of the memory, start from the begining
      {
      df_Read_PageAdr = 0;
      df_Read_END = true;
      }
    }
  return result;
}
//----------
ISR(TIMER1_COMPA_vect) {
      
     unsigned char temp;
        temp = ReadByte();
        OCR1B = temp;
}
//----------
void main(void)
{
   Init();

}

// AT45DB161D Commands (from Datasheet)
#define DF_TRANSFER_PAGE_TO_BUFFER_1   0x53
#define DF_TRANSFER_PAGE_TO_BUFFER_2   0x55
#define DF_STATUS_REGISTER_READ   0xD7
#define DF_READ_MANUFACTURER_AND_DEVICE_ID   0x9F
#define DF_PAGE_READ   0xD2
#define DF_BUFFER_1_READ   0xD4
#define DF_BUFFER_2_READ   0xD6
#define DF_BUFFER_1_WRITE   0x84
#define DF_BUFFER_2_WRITE   0x87
#define DF_BUFFER_1_TO_PAGE_WITH_ERASE   0x83
#define DF_BUFFER_2_TO_PAGE_WITH_ERASE   0x86
#define DF_PAGE_ERASE   0x81
#define DF_BLOCK_ERASE   0x50
#define DF_SECTOR_ERASE   0x7C
#define DF_CHIP_ERASE_0   0xC7
#define DF_CHIP_ERASE_1   0x94
#define DF_CHIP_ERASE_2   0x80
#define DF_CHIP_ERASE_3   0x9A

#define false 0
#define true 1