sample-mmc.c

非常好用的嵌入式系统用的fat文件系统,支持fat12 fat16 fat32

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


#include <avr/io.h>
#include "diskio.h"


/* Definitions for MMC/SDC command */
#define CMD0    (0x40+0)    /* GO_IDLE_STATE */
#define CMD1    (0x40+1)    /* SEND_OP_COND */
#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 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 */
#define CMD24    (0x40+24)    /* WRITE_BLOCK */
#define CMD25    (0x40+25)    /* WRITE_MULTIPLE_BLOCK */
#define CMD41    (0x40+41)    /* SEND_OP_COND (ACMD) */
#define CMD55    (0x40+55)    /* APP_CMD */
#define CMD58    (0x40+58)    /* READ_OCR */


/* Port Controls  (Platform dependent) */
#define SELECT()    PORTB &= ~1        /* MMC CS = L */
#define    DESELECT()    PORTB |= 1        /* MMC CS = H */

#define SOCKPORT    PINB            /* Socket contact port */
#define SOCKWP        0x20            /* Write protect switch (PB5) */
#define SOCKINS        0x10            /* Card detect switch (PB4) */



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

   Module Private Functions

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

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

static volatile
BYTE Timer1, Timer2;    /* 100Hz decrement timer */

static
BYTE CardType;            /* b0:MMC, b1:SDC, b2:Block addressing */



/*-----------------------------------------------------------------------*/
/* Transmit a byte to MMC via SPI  (Platform dependent)                  */
/*-----------------------------------------------------------------------*/

#define xmit_spi(dat)     SPDR=(dat); loop_until_bit_is_set(SPSR,SPIF)



/*-----------------------------------------------------------------------*/
/* Receive a byte from MMC via SPI  (Platform dependent)                 */
/*-----------------------------------------------------------------------*/

static
BYTE rcvr_spi (void)
{
    SPDR = 0xFF;
    loop_until_bit_is_set(SPSR, SPIF);
    return SPDR;
}

/* Alternative macro to receive data fast */
#define rcvr_spi_m(dst)    SPDR=0xFF; loop_until_bit_is_set(SPSR,SPIF); *(dst)=SPDR



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

static
BYTE wait_ready (void)
{
    BYTE res;


    Timer2 = 50;    /* Wait for ready in timeout of 500ms */
    rcvr_spi();
    do
        res = rcvr_spi();
    while ((res != 0xFF) && Timer2);

    return res;
}



/*-----------------------------------------------------------------------*/
/* 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)
{
    PORTE &= ~0x80;                /* Socket power ON */
    for (Timer1 = 3; Timer1; );    /* Wait for 30ms */
    PORTB = 0b10110101;            /* Enable drivers */
    DDRB  = 0b11000111;
    SPCR = 0b01010000;            /* Initialize SPI port (Mode 0) */
    SPSR = 0b00000001;
}

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

    SPCR = 0;                /* Disable SPI function */
    DDRB  = 0b11000000;        /* Disable drivers */
    PORTB = 0b10110000;
    PORTE |=  0x80;            /* Socket power OFF */
    Stat |= STA_NOINIT;        /* Set STA_NOINIT */
}

static
int chk_power(void)        /* Socket power state: 0=off, 1=on */
{
    return (PORTE & 0x80) ? 0 : 1;
}



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

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


    Timer1 = 10;
    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++);
    } while (btr -= 2);
    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, wc;


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

    xmit_spi(token);                    /* Xmit data token */
    if (token != 0xFD) {    /* Is data token */
        wc = 0;
        do {                            /* Xmit the 512 byte data block to MMC */
            xmit_spi(*buff++);
            xmit_spi(*buff++);
        } while (--wc);
        xmit_spi(0xFF);                    /* CRC (Dummy) */
        xmit_spi(0xFF);
        resp = rcvr_spi();                /* Reveive 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 (wait_ready() != 0xFF) return 0xFF;

    /* Send command packet */
    xmit_spi(cmd);                        /* Command */
    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 = 0;
    if (cmd == CMD0) n = 0x95;            /* CRC for CMD0(0) */
    if (cmd == CMD8) n = 0x87;            /* 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, 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 */

    SELECT();                /* CS = L */
    ty = 0;
    if (send_cmd(CMD0, 0) == 1) {            /* Enter Idle state */
        Timer1 = 100;                        /* Initialization timeout of 1000 msec */
        if (send_cmd(CMD8, 0x1AA) == 1) {    /* SDC Ver2+ */
            for (n = 0; n < 4; n++) ocr[n] = rcvr_spi();
            if (ocr[2] == 0x01 && ocr[3] == 0xAA) {    /* The card can work at vdd range of 2.7-3.6V */
                do {