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#include <avr/io.h>

#include <util/delay.h>

#include "fat16.h"

#include "sdc.h"

#include "ssc.h"

//________________________________________________________________________________________________________________________________________

// Module name:			mmc.c

// Compiler used:		avr-gcc 3.4.5

// Last Modifikation:	24.07.2007

// Version:				1.05

// Authors:				Stephan Busker

// Description:			Source files for connecting to an sdcard using the SSC

//

//........................................................................................................................................

// Functions:			u8			SDC_init(void);

//						u8 SDC_PutCommand (u8*CMD);

//						u8 SDC_PutSector(u32 addr,u8*Buffer);

//						u8 SDC_GetSector(u32 addr,u8*Buffer);

//						void SDC_GetBlock(u8*CMD,u8*Buffer,u16 Bytes);

//

////........................................................................................................................................

// ext. functions:		extern void SSC_Init(void);

//						extern u8 SSC_GetChar (void);

//						extern void SSC_PutChar (u8);

//						extern void SSC_Enable(void);

//						extern void SSC_Disable(void);

//........................................................................................................................................

//

// URL:					www.Mikro-Control.de

// mailto:				stephan.busker@mikro-control.de

//________________________________________________________________________________________________________________________________________

//________________________________________________________________________________________________________________________________________

// Funtion: 	SDC_Init(void);

//

// Description:	This function initialises the SDCard to spi-mode.

//

//

// Returnvalue: the function returns 0 if the initialisation was successfull otherwise the function returns an errorcode.

//________________________________________________________________________________________________________________________________________

u8 SDC_Init(void)

{

	u8 Timeout = 0;

	u8 CMD[] = {0x40,0x00,0x00,0x00,0x00,0x95};

	u16 a = 0;

	u8 	b = 0;

	SSC_Init();														// Initialise SSC to transmit data to the sdcard.

	_delay_ms(10);													// before initialising the sdcard wait for 10ms

	for (b=0;b<0x0f;b++) 											// sending 74Clocks brings the sdcard into spimode.

	{

		_delay_us(1);												// wait at least 1us between the characters.

		SSC_PutChar(0xff);

	}

	while(SDC_PutCommand (CMD) !=1)								// Sending CMD0 (Reset) to the sdcard.

	{

		if (Timeout++ > 200)

		{

			return(1);

		}

	}

	Timeout = 0;

	CMD[0] = 0x41;

	CMD[5] = 0xFF;

	while( SDC_PutCommand (CMD) !=0)								// Sending CMD1 to the sdcard.

	{

		if (Timeout++ > 100)

		{

			return(2);

		}

	}

	SSC_Disable();													// disable sdcard.

	return(0);

}

//________________________________________________________________________________________________________________________________________

// Funtion: 	SDC_PutCommand(* CMD);

//

// Description:	This function initialises the SDCard to spi-mode.

//

//

// Returnvalue: the function returns 0 if the initialisation was successfull otherwise the function returns an errorcode.

//________________________________________________________________________________________________________________________________________

u8 SDC_PutCommand (u8*CMD)

{

	u8 tmp = 0xff;

	u8 Timeout = 0;

	u16 a = 0;

	#ifdef SSC_RX_FIFO

	SSC_ClearRxFifo();

	#endif

	SSC_Disable();														// disable chipselect

	SSC_PutChar(0xFF);													// Send 8 Clocks to the sdcard while card is not selected.

	SSC_Enable();														// enable chipselect.

    if (*CMD == 0x41) _delay_ms(10);									// if command is CMD0 generate a short delay.

	for (a = 0;a<0x06;a++) 											// send the command sequence to the sdcard (6 bytes)

	{

		SSC_PutChar(*CMD++);

	}

	#ifdef SSC_RX_FIFO

	SSC_ClearRxFifo();

	#endif

	while (tmp == 0xff)													// Wait for response from sdcard.

	{

		tmp = SSC_GetChar();

		if (Timeout++ > 100)

		{

			break; 														// or timeout.

		}

	}

	return(tmp);

}

//________________________________________________________________________________________________________________________________________

// Funtion: 	SDC_PutSector(void);

//

// Description:	This function writes one sector of data to the SSC

//

//

// Returnvalue: none

//________________________________________________________________________________________________________________________________________

u8 SDC_PutSector(u32 addr,u8*Buffer)

{

	u8 tmp;

	u8 CMD[] = {0x58,0x00,0x00,0x00,0x00,0xFF};

	addr = addr << 9; 													// convert sectoradress to byteadress

	CMD[1] = ((addr & 0xFF000000) >>24 );

	CMD[2] = ((addr & 0x00FF0000) >>16 );

	CMD[3] = ((addr & 0x0000FF00) >>8 );

	tmp = SDC_PutCommand (CMD);										// send command to sdcard.

	if (tmp != 0)

	{

		return(tmp);

	}

	#ifdef SSC_RX_FIFO

	SSC_ClearRxFifo();

	#endif

	for (u8 a=0;a<100;a++)								// wait until sdcard is ready

	{

		SSC_GetChar();

	}

	SSC_PutChar(0xFE);													// send start of header to the SSC

	for (u16 a=0;a<512;a++)								// transmitt one sector (normaly 512bytes) of data to the sdcard.

	{

		SSC_PutChar(*Buffer++);

	}

	SSC_PutChar(0xFF); 													// write two bytes of crc to the sdcard (not used in spi-mode)

	SSC_PutChar(0xFF);

	#ifdef SSC_RX_FIFO

	SSC_ClearRxFifo();

	#endif

	while (SSC_GetChar() != 0xff){};									// wait untile the sdcard is ready.

	SSC_Disable();														// disable sdcard.

	return(0);

}

//________________________________________________________________________________________________________________________________________

// Funtion: 	SDC_GetSector(u32 addr,u8*Buffer);

//

// Description:	This function reads one sector of data from the SSC

//

//

// Returnvalue: none

//________________________________________________________________________________________________________________________________________

u8 SDC_GetSector(u32 addr,u8*Buffer)

{

	u8 CMD[] = {0x51,0x00,0x00,0x00,0x00,0xFF};

	addr = addr << 9; 													// convert sectoradress to byteadress.

	CMD[1] = ((addr & 0xFF000000) >>24 );

	CMD[2] = ((addr & 0x00FF0000) >>16 );

	CMD[3] = ((addr & 0x0000FF00) >>8 );

	SDC_GetBlock(CMD,Buffer,512);									// read specified sector from sdcard.

	return(0);

}

//________________________________________________________________________________________________________________________________________

// Funtion: 	SDC_GetBlock(void);

//

// Description:	This function reads one block of data of s16 bytes from the SSC.

//

//

// Returnvalue: the function returns 0 if the initialisation was successfull otherwise the function returns an errorcode.

//________________________________________________________________________________________________________________________________________

void SDC_GetBlock(u8*CMD,u8*Buffer,u16 Bytes)

{

	if (SDC_PutCommand (CMD) != 0)										// Send command to the sdcard.

	{

		return;

	}

	#ifdef SSC_RX_FIFO

	SSC_ClearRxFifo();

	#endif

	while (SSC_GetChar() != 0xfe){};										// wait until the sdcard is ready to transmitt data.

	for (u16 a=0;a<Bytes;a++)									// read the block from the SSC (normaly 512Bytes)

	{

		*Buffer++ = SSC_GetChar();

	}

	SSC_GetChar();															// Read two bytes CRC- checksum (not used in spi-mode)

	SSC_GetChar();

	SSC_Disable();															// disable sdcard.

}