/******** Example Code : Accessing Atmel AT45Dxxx dataflash on STK500 *******

Device      : 	AT90S8515

File name   : 	dataflash.c

Description : 	Functions to access the Atmel AT45Dxxx dataflash series
      				  Supports 512Kbit - 64Mbit
                 
Last change:    16 Aug 2001   AS
 
****************************************************************************/

#define  __IAR_SYSTEMS_ASM__ 

// Includes
//#include <INA90.H>
//#include <io8515.h>

#include "D:\ICC_H\dataflash.h"

// Constants
//Look-up table for these sizes ->  512k, 1M, 2M, 4M, 8M, 16M, 32M, 64M
flash unsigned char DF_pagebits[]  ={  9,  9,  9,  9,  9,  10,  10,  11};	//index of internal page address bits

// Globals
unsigned char PageBits;

// Functions

/*****************************************************************************
*
*	Function name : DF_SPI_init
*
*	Returns :		None
*
*	Parameters :	None
*
*	Purpose :		Sets up the HW SPI in Master mode, Mode 3
*					Note -> Uses the SS line to control the DF CS-line.
*
******************************************************************************/
void DF_SPI_init (void)
{
	//PORTB= (1<<PORTB);									//Set SS high		
	//DDRB = (1<<PB4) | (1<<PB5)| (1<<PB7);					//Set SS, MOSI and SCK as outputs
	
	SPCR = (1<<SPE) | (1<<MSTR) | (1<<CPHA) | (1<<CPOL);	//Enable SPI in Master mode, mode 3
//SPCR=0x51;
}


/*****************************************************************************
*
*	Function name : DF_SPI_RW
*
*	Returns :		Byte read from SPI data register (any value)
*
*	Parameters :	Byte to be written to SPI data register (any value)
*
*	Purpose :		Read and writes one byte from/to SPI master
*
******************************************************************************/
unsigned char DF_SPI_RW (unsigned char output)
{
	unsigned char input;
	
	SPDR = output;							//put byte 'output' in SPI data register
	while(!(SPSR & 0x80));					//wait for transfer complete, poll SPIF-flag
	input = SPDR;							//read value in SPI data reg.
	
	return input;							//return the byte clocked in from SPI slave
}		


/*****************************************************************************
*
*	Function name : Read_DF_status
*
*	Returns :		One status byte. Consult Dataflash datasheet for further
*					decoding info
*
*	Parameters :	None
*
*	Purpose :		Status info concerning the Dataflash is busy or not.
*					Status info concerning compare between buffer and flash page
*					Status info concerning size of actual device
*
******************************************************************************/
unsigned char Read_DF_status (void)
{
	unsigned char result,index_copy;
	
	DF_CS_inactive;							//make sure to toggle CS signal in order
	DF_CS_active;							//to reset dataflash command decoder
	result = DF_SPI_RW(StatusReg);			//send status register read op-code
	result = DF_SPI_RW(0x00);				//dummy write to get result
	
	index_copy = ((result & 0x38) >> 3);	//get the size info from status register
	PageBits   = DF_pagebits[index_copy];	//get number of internal page address bits from look-up table
	
	return result;							//return the read status register value
}


/*****************************************************************************
*
*	Function name : Page_To_Buffer
*
*	Returns :		None
*
*	Parameters :	BufferNo	->	Decides usage of either buffer 1 or 2
*					PageAdr		->	Address of page to be transferred to buffer
*
*	Purpose :		Transfers a page from flash to dataflash SRAM buffer
*					
******************************************************************************/
void Page_To_Buffer (unsigned int PageAdr, unsigned char BufferNo)
{
	DF_CS_inactive;												//make sure to toggle CS signal in order
	DF_CS_active;												//to reset dataflash command decoder
	
	if (1 == BufferNo)											//transfer flash page to buffer 1
	{
		DF_SPI_RW(FlashToBuf1Transfer);							//transfer to buffer 1 op-code
		DF_SPI_RW((unsigned char)(PageAdr >> (16 - PageBits)));	//upper part of page address
		DF_SPI_RW((unsigned char)(PageAdr << (PageBits - 8)));	//lower part of page address
		DF_SPI_RW(0x00);										//don't cares
	}
	else	
	if (2 == BufferNo)											//transfer flash page to buffer 2
	{
		DF_SPI_RW(FlashToBuf2Transfer);							//transfer to buffer 2 op-code
		DF_SPI_RW((unsigned char)(PageAdr >> (16 - PageBits)));	//upper part of page address
		DF_SPI_RW((unsigned char)(PageAdr << (PageBits - 8)));	//lower part of page address
		DF_SPI_RW(0x00);										//don't cares
	}
	
	DF_CS_inactive;												//initiate the transfer
	DF_CS_active;
	
	while(!(Read_DF_status() & 0x80));							//monitor the status register, wait until busy-flag is high
}



/*****************************************************************************
*
*	Function name : Buffer_Read_Byte
*
*	Returns :		One read byte (any value)
*
*	Parameters :	BufferNo	->	Decides usage of either buffer 1 or 2
*					IntPageAdr	->	Internal page address
*
*	Purpose :		Reads one byte from one of the dataflash
*					internal SRAM buffers
*
******************************************************************************/
unsigned char Buffer_Read_Byte (unsigned char BufferNo, unsigned int IntPageAdr)
{
	unsigned char data;
	
	DF_CS_inactive;								//make sure to toggle CS signal in order
	DF_CS_active;								//to reset dataflash command decoder
	
	if (1 == BufferNo)							//read byte from buffer 1
	{
		DF_SPI_RW(Buf1Read);					//buffer 1 read op-code
		DF_SPI_RW(0x00);						//don't cares
		DF_SPI_RW((unsigned char)(IntPageAdr>>8));//upper part of internal buffer address
		DF_SPI_RW((unsigned char)(IntPageAdr));	//lower part of internal buffer address
		DF_SPI_RW(0x00);						//don't cares
		data = DF_SPI_RW(0x00);					//read byte
	}
	else
	if (2 == BufferNo)							//read byte from buffer 2
	{
		DF_SPI_RW(Buf2Read);					//buffer 2 read op-code
		DF_SPI_RW(0x00);						//don't cares
		DF_SPI_RW((unsigned char)(IntPageAdr>>8));//upper part of internal buffer address
		DF_SPI_RW((unsigned char)(IntPageAdr));	//lower part of internal buffer address
		DF_SPI_RW(0x00);						//don't cares
		data = DF_SPI_RW(0x00);					//read byte
	}
	
	return data;								//return the read data byte
}



/*****************************************************************************
*
*	Function name : Buffer_Read_Str
*
*	Returns :		None
*
*	Parameters :	BufferNo	->	Decides usage of either buffer 1 or 2
*					IntPageAdr	->	Internal page address
*					No_of_bytes	->	Number of bytes to be read
*					*BufferPtr	->	address of buffer to be used for read bytes
*
*	Purpose :		Reads one or more bytes from one of the dataflash
*					internal SRAM buffers, and puts read bytes into
*					buffer pointed to by *BufferPtr
*
******************************************************************************/
void Buffer_Read_Str (unsigned char BufferNo, unsigned int IntPageAdr, unsigned int No_of_bytes, unsigned char *BufferPtr)
{
	unsigned int i;

	DF_CS_inactive;								//make sure to toggle CS signal in order
	DF_CS_active;								//to reset dataflash command decoder
	
	if (1 == BufferNo)							//read byte(s) from buffer 1
	{
		DF_SPI_RW(Buf1Read);					//buffer 1 read op-code
		DF_SPI_RW(0x00);						//don't cares
		DF_SPI_RW((unsigned char)(IntPageAdr>>8));//upper part of internal buffer address
		DF_SPI_RW((unsigned char)(IntPageAdr));	//lower part of internal buffer address
		DF_SPI_RW(0x00);						//don't cares
		for( i=0; i<No_of_bytes; i++)
		{
			*(BufferPtr) = DF_SPI_RW(0x00);		//read byte and put it in AVR buffer pointed to by *BufferPtr
			BufferPtr++;						//point to next element in AVR buffer