mmc.c

FAT16 Microchip Application not for PIC24F

/*-----------------------------------------------------------------------*/
/* MMC/SDSC/SDHC (in SPI mode) control module  (C)ChaN, 2007             */
/*-----------------------------------------------------------------------*/
/* Only rcvr_spi(), xmit_spi(), disk_timerproc() and some macros         */
/* are platform dependent.                                               */
/*-----------------------------------------------------------------------*/


#include <p24fj128ga106.h>
#include "HardwareProfile.h"
#include "diskio.h"



/* Definitions for MMC/SDC command */
#define CMD0	(0x40+0)	/* GO_IDLE_STATE */
#define CMD1	(0x40+1)	/* SEND_OP_COND (MMC) */
#define ACMD41	(0xC0+41)	/* SEND_OP_COND (SDC) */
#define CMD8	(0x40+8)	/* SEND_IF_COND */
#define CMD9	(0x40+9)	/* SEND_CSD */
#define CMD10	(0x40+10)	/* SEND_CID */
#define CMD12	(0x40+12)	/* STOP_TRANSMISSION */
#define ACMD13	(0xC0+13)	/* SD_STATUS (SDC) */
#define CMD16	(0x40+16)	/* SET_BLOCKLEN */
#define CMD17	(0x40+17)	/* READ_SINGLE_BLOCK */
#define CMD18	(0x40+18)	/* READ_MULTIPLE_BLOCK */
#define CMD23	(0x40+23)	/* SET_BLOCK_COUNT (MMC) */
#define ACMD23	(0xC0+23)	/* SET_WR_BLK_ERASE_COUNT (SDC) */
#define CMD24	(0x40+24)	/* WRITE_BLOCK */
#define CMD25	(0x40+25)	/* WRITE_MULTIPLE_BLOCK */
#define CMD55	(0x40+55)	/* APP_CMD */
#define CMD58	(0x40+58)	/* READ_OCR */


/* Port Controls  (Platform dependent) */
#define SELECT()	 	SDCS = 0	/* MMC CS = L */
#define DESELECT() 		SDCS = 1	/* MMC CS = H */

//#define SOCKPORT	PORTB		/* Socket contact port */
//#define SOCKWP	(1<<10)		/* Write protect switch (RB10) */
//#define SOCKINS	(1<<11)		/* Card detect switch (RB11) */



/*--------------------------------------------------------------------------

   Module Private Functions

---------------------------------------------------------------------------*/

static volatile
DSTATUS Stat = STA_NOINIT;	/* Disk status */

static volatile
UINT Timer1, Timer2;		/* 1000Hz decrement timer */

static
UINT CardType;			/* b0:MMC, b1:SDv1, b2:SDv2, b3:Block addressing */



/*-----------------------------------------------------------------------*/
/* Exchange a byte between PIC and MMC via SPI  (Platform dependent)     */
/*-----------------------------------------------------------------------*/

#define xmit_spi(dat) 	xchg_spi(dat)
#define rcvr_spi()	xchg_spi(0xFF)
#define rcvr_spi_m(p)	SPI2BUF = 0xFF; while (!SPI2STATbits.SPIRBF); *(p) = (BYTE)SPI2BUF;

static
BYTE xchg_spi (BYTE dat)
{
	SPI2BUF = dat;
	while (!SPI2STATbits.SPIRBF);
	return (BYTE)SPI2BUF;
}


/*-----------------------------------------------------------------------*/
/* Wait for card ready                                                   */
/*-----------------------------------------------------------------------*/

static
BYTE wait_ready (void)
{
	BYTE res;


	Timer2 = 500;	/* Wait for ready in timeout of 500ms */
	rcvr_spi();
	do
		res = rcvr_spi();
	while ((res != 0xFF) && Timer2);

	return res;
}



/*-----------------------------------------------------------------------*/
/* Deselect the card and release SPI bus                                 */
/*-----------------------------------------------------------------------*/

static
void release_spi (void)
{
	DESELECT();
	rcvr_spi();
}



/*-----------------------------------------------------------------------*/
/* Power Control  (Platform dependent)                                   */
/*-----------------------------------------------------------------------*/
/* When the target system does not support socket power control, there   */
/* is nothing to do in these functions and chk_power always returns 1.   */

static
void power_on (void)
{
							/* Enable SPI2 */
	SPI2CON1 = 0x013B;
	SPI2CON2 = 0x0000;
	SPI2STATbits.SPIEN = 1;
}

static
void power_off (void)
{
	SELECT();				/* Wait for card ready */
	wait_ready();
	release_spi();

	SPI2STATbits.SPIEN = 0;				/* Disable SPI2 */

	Stat |= STA_NOINIT;		/* Set STA_NOINIT */
}



/*-----------------------------------------------------------------------*/
/* Receive a data packet from MMC                                        */
/*-----------------------------------------------------------------------*/

static
BOOL rcvr_datablock (
	BYTE *buff,			/* Data buffer to store received data */
	UINT btr				/* Byte count (must be multiple of 4) */
)
{
	BYTE token;


	Timer1 = 100;
	do {								/* Wait for data packet in timeout of 100ms */
		token = rcvr_spi();
	} while ((token == 0xFF) && Timer1);

	if(token != 0xFE) return FALSE;		/* If not valid data token, retutn with error */

	do {								/* Receive the data block into buffer */
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
		rcvr_spi_m(buff++);
	} while (btr -= 4);
	rcvr_spi();						/* Discard CRC */
	rcvr_spi();

	return TRUE;						/* Return with success */
}



/*-----------------------------------------------------------------------*/
/* Send a data packet to MMC                                             */
/*-----------------------------------------------------------------------*/

#if _READONLY == 0
static
BOOL xmit_datablock (
	const BYTE *buff,		/* 512 byte data block to be transmitted */
	BYTE token			/* Data/Stop token */
)
{
	BYTE resp;
	UINT bc = 512;


	if (wait_ready() != 0xFF) return FALSE;

	xmit_spi(token);			/* Xmit data token */
	if (token != 0xFD) {	/* Is data token */
		do {						/* Xmit the 512 byte data block to MMC */
			xmit_spi(*buff++);
			xmit_spi(*buff++);
		} while (bc -= 2);
		xmit_spi(0xFF);				/* CRC (Dummy) */
		xmit_spi(0xFF);
		resp = rcvr_spi();			/* Receive data response */
		if ((resp & 0x1F) != 0x05)	/* If not accepted, return with error */
			return FALSE;
	}

	return TRUE;
}
#endif	/* _READONLY */



/*-----------------------------------------------------------------------*/
/* Send a command packet to MMC                                          */
/*-----------------------------------------------------------------------*/

static
BYTE send_cmd (
	BYTE cmd,		/* Command byte */
	DWORD arg		/* Argument */
)
{
	BYTE n, res;


	if (cmd & 0x80) {	/* ACMD<n> is the command sequense of CMD55-CMD<n> */
		cmd &= 0x7F;
		res = send_cmd(CMD55, 0);
		if (res > 1) return res;
	}

	/* Select the card and wait for ready */
	DESELECT();
	SELECT();
	if (wait_ready() != 0xFF) return 0xFF;

	/* Send command packet */
	xmit_spi(cmd);						/* Start + Command index */
	xmit_spi((BYTE)(arg >> 24));		/* Argument[31..24] */
	xmit_spi((BYTE)(arg >> 16));		/* Argument[23..16] */
	xmit_spi((BYTE)(arg >> 8));			/* Argument[15..8] */
	xmit_spi((BYTE)arg);				/* Argument[7..0] */
	n = 0x01;							/* Dummy CRC + Stop */
	if (cmd == CMD0) n = 0x95;			/* Valid CRC for CMD0(0) */
	if (cmd == CMD8) n = 0x87;			/* Valid CRC for CMD8(0x1AA) */
	xmit_spi(n);

	/* Receive command response */
	if (cmd == CMD12) rcvr_spi();		/* Skip a stuff byte when stop reading */
	n = 10;								/* Wait for a valid response in timeout of 10 attempts */
	do
		res = rcvr_spi();
	while ((res & 0x80) && --n);

	return res;			/* Return with the response value */
}



/*--------------------------------------------------------------------------

   Public Functions

---------------------------------------------------------------------------*/


/*-----------------------------------------------------------------------*/
/* Initialize Disk Drive                                                 */
/*-----------------------------------------------------------------------*/

DSTATUS disk_initialize (
	BYTE drv		/* Physical drive nmuber (0) */
)
{
	BYTE n, cmd, ty, ocr[4];


	if (drv) return STA_NOINIT;			/* Supports only single drive */
	if (Stat & STA_NODISK) return Stat;	/* No card in the socket */

	power_on();							/* Force socket power on */
	for (n = 10; n; n--) rcvr_spi();	/* 80 dummy clocks */