PokittoLib

File content as of revision 50:ca94812a17b6:

/*-----------------------------------------------------------------------*/
/* PFF - Low level disk control module for ATtiny85     (C)ChaN, 2009    */
/*-----------------------------------------------------------------------*/

#define _WRITE_FUNC    1

#include "diskio.h"
#include "mbed.h"
#include "connect.h"
#include "PokittoDisk.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 CMD16    (0x40+16)    /* SET_BLOCKLEN */
#define CMD17    (0x40+17)    /* READ_SINGLE_BLOCK */
#define CMD24    (0x40+24)    /* WRITE_BLOCK */
#define CMD55    (0x40+55)    /* APP_CMD */
#define CMD58    (0x40+58)    /* READ_OCR */



/* Port Controls (Platform dependent) */
#define SELECT()    CLR_SD_CS //mmccs.write(0)        /* MMC CS = L */
#define    DESELECT()    SET_SD_CS // mmccs.write(1)        /* MMC CS = H */
#define    MMC_SEL        !GET_SD_CS // !mmccs.read()    /* MMC CS status (true:selected) */

void xmit_spi (BYTE c) {
    device.write(c);    /* Send a byte */
}

BYTE rcv_spi (void) {
    return device.write(0xff);
}

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

   Module Private Functions

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

static
BYTE CardType;


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

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


/*-----------------------------------------------------------------------*/
/* 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 */
    DESELECT();
    rcv_spi();
    SELECT();
    rcv_spi();

    /* Send a 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 a command response */
    n = 10;                                /* Wait for a valid response in timeout of 10 attempts */
    do {
        res = rcv_spi();
    } while ((res & 0x80) && --n);

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



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

   Public Functions

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


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

//__attribute__((section(".SD_Code")))
DSTATUS disk_initialize (void) {
    BYTE n, cmd, ty, ocr[4];
    WORD tmr;

    DESELECT();
    device.frequency(SPI_FREQ);
    device.format(8);
    // device.frequency(SPI_FREQ); // hangs if this is after format

#if _WRITE_FUNC
    if (MMC_SEL) disk_writep(0, 0);        /* Finalize write process if it is in progress */
#endif
    for (n = 100; n; n--) rcv_spi();    /* Dummy clocks */

    ty = 0;
    if (send_cmd(CMD0, 0) == 1) {            /* Enter Idle state */
        if (send_cmd(CMD8, 0x1AA) == 1) {    /* SDv2 */
            for (n = 0; n < 4; n++) ocr[n] = rcv_spi();        /* Get trailing return value of R7 resp */
            if (ocr[2] == 0x01 && ocr[3] == 0xAA) {                /* The card can work at vdd range of 2.7-3.6V */
                for (tmr = 12000; tmr && send_cmd(ACMD41, 1UL << 30); tmr--) ;    /* Wait for leaving idle state (ACMD41 with HCS bit) */
                if (tmr && send_cmd(CMD58, 0) == 0) {        /* Check CCS bit in the OCR */
                    for (n = 0; n < 4; n++) ocr[n] = rcv_spi();
                    ty = (ocr[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2;    /* SDv2 (HC or SC) */
                }
            }
        } else {                            /* SDv1 or MMCv3 */
            if (send_cmd(ACMD41, 0) <= 1)     {
                ty = CT_SD1;
                cmd = ACMD41;    /* SDv1 */
            } else {
                ty = CT_MMC;
                cmd = CMD1;    /* MMCv3 */
            }
            for (tmr = 25000; tmr && send_cmd(cmd, 0); tmr--) ;    /* Wait for leaving idle state */
            if (!tmr || send_cmd(CMD16, 512) != 0)            /* Set R/W block length to 512 */
                ty = 0;
        }
    }
    CardType = ty;
    release_spi();

    return ty ? 0 : STA_NOINIT;
}



/*-----------------------------------------------------------------------*/
/* Read partial sector                                                   */
/*-----------------------------------------------------------------------*/

DRESULT disk_readp (
    BYTE *buff,        /* Pointer to the read buffer (NULL:Read bytes are forwarded to the stream) */
    DWORD lba,        /* Sector number (LBA) */
    WORD ofs,        /* Byte offset to read from (0..511) */
    WORD cnt        /* Number of bytes to read (ofs + cnt mus be <= 512) */
) {
    DRESULT res;
    BYTE rc;
    WORD bc;


    if (!(CardType & CT_BLOCK)) lba *= 512;        /* Convert to byte address if needed */

    res = RES_ERROR;
    if (send_cmd(CMD17, lba) == 0) {        /* READ_SINGLE_BLOCK */

        bc = 30000;
        do {                            /* Wait for data packet in timeout of 100ms */
            rc = rcv_spi();
        } while (rc == 0xFF && --bc);

        if (rc == 0xFE) {                /* A data packet arrived */
            bc = 514 - ofs - cnt;

            /* Skip leading bytes */
            if (ofs) {
                do {
                    rcv_spi();
                } while (--ofs);
            }

            /* Receive a part of the sector */
            if (buff) {    /* Store data to the memory */
                do {
                    *buff++ = rcv_spi();
                } while (--cnt);
            } else {    /* Forward data to the outgoing stream (depends on the project) */
                do {
                    rcv_spi();
                } while (--cnt);
            }

            /* Skip trailing bytes and CRC */
            do rcv_spi();
            while (--bc);

            res = RES_OK;
        }
    }

    release_spi();

    return res;
}



/*-----------------------------------------------------------------------*/
/* Write partial sector                                                  */
/*-----------------------------------------------------------------------*/
#if _WRITE_FUNC

DRESULT disk_writep (
    const BYTE *buff,    /* Pointer to the bytes to be written (NULL:Initiate/Finalize sector write) */
    DWORD sa            /* Number of bytes to send, Sector number (LBA) or zero */
) {
    DRESULT res;
    WORD bc;
    static WORD wc;


    res = RES_ERROR;

    if (buff) {        /* Send data bytes */
        bc = (WORD)sa;
        while (bc && wc) {        /* Send data bytes to the card */
            xmit_spi(*buff++);
            wc--;
            bc--;
        }
        res = RES_OK;
    } else {
        if (sa) {    /* Initiate sector write process */
            if (!(CardType & CT_BLOCK)) sa *= 512;    /* Convert to byte address if needed */
            if (send_cmd(CMD24, sa) == 0) {            /* WRITE_SINGLE_BLOCK */
                xmit_spi(0xFF);
                xmit_spi(0xFE);        /* Data block header */
                wc = 512;                            /* Set byte counter */
                res = RES_OK;
            }
        } else {    /* Finalize sector write process */
            bc = wc + 2;
            while (bc--) xmit_spi(0);    /* Fill left bytes and CRC with zeros */
            if ((rcv_spi() & 0x1F) == 0x05) {    /* Receive data resp and wait for end of write process in timeout of 300ms */
                for (bc = 65000; rcv_spi() != 0xFF && bc; bc--) ;    /* Wait ready */
                if (bc) res = RES_OK;
            }
            release_spi();
        }
    }

    return res;
}
#endif