Example #1
0
/**
 * \ingroup sd_raw
 * Initialize the SPI port as slave
 *
 * \return nothing
 */
void sd_raw_spi_init(void)
{
  uint8_t b;
  // SS input
  configure_pin_ss();
  // SCK input
  configure_pin_sck();
  // MOSI input
  configure_pin_mosi();
  // MISO output
  configure_pin_miso();

  // enable double-speed
  // NOT WORKING YET
  //SPSR |= (1 << SPI2X);

  // enable SPI
  SPCR = (1 << SPE);

  // reading these two register should start spi
  b = SPDR;
  b = SPSR;

  return;
}
Example #2
0
/**
 * \ingroup sd_raw
 * Initializes memory card communication.
 *
 * \returns 0 on failure, 1 on success.
 */
uint8_t sd_raw_init()
{
  uint16_t i;
  uint8_t response;

    /* enable inputs for reading card status */
    configure_pin_available();
    configure_pin_locked();

    /* enable outputs for MOSI, SCK, SS, input for MISO */
    configure_pin_mosi();
    configure_pin_sck();
    configure_pin_ss();
    configure_pin_miso();

    unselect_card();

    /* initialize SPI with lowest frequency; max. 400kHz during identification mode of card */
    SPCR = (0 << SPIE) | /* SPI Interrupt Enable */
           (1 << SPE)  | /* SPI Enable */
           (0 << DORD) | /* Data Order: MSB first */
           (1 << MSTR) | /* Master mode */
           (0 << CPOL) | /* Clock Polarity: SCK low when idle */
           (0 << CPHA) | /* Clock Phase: sample on rising SCK edge */
           (1 << SPR1) | /* Clock Frequency: f_OSC / 128 */
           (1 << SPR0);
    SPSR &= ~(1 << SPI2X); /* No doubled clock frequency */

    /* initialization procedure */
    
    if(!sd_raw_available())
        return 0;

    /* card needs 74 cycles minimum to start up */
    for(i = 0; i < 10; ++i)
    {
        /* wait 8 clock cycles */
        sd_raw_rec_byte();
    }

    /* address card */
    select_card();

    /* reset card */
    for(i = 0; ; ++i)
    {
        response = sd_raw_send_command_r1(CMD_GO_IDLE_STATE, 0);
        if(response == (1 << R1_IDLE_STATE))
            break;

        if(i == 0x1ff)
        {
            unselect_card();
            return 0;
        }
    }
    
    /* wait for card to get ready */
    for(i = 0; ; ++i)
    {
        response = sd_raw_send_command_r1(CMD_SEND_OP_COND, 0);
        if(!(response & (1 << R1_IDLE_STATE)))
            break;

        if(i == 0x7fff)
        {
            unselect_card();
            return 0;
        }
    }

    /* set block size to 512 bytes */
    if(sd_raw_send_command_r1(CMD_SET_BLOCKLEN, 512))
    {
        unselect_card();
        return 0;
    }

    /* deaddress card */
    unselect_card();

    /* switch to highest SPI frequency possible */
    SPCR &= ~((1 << SPR1) | (1 << SPR0)); /* Clock Frequency: f_OSC / 4 */
    SPSR |= (1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */

#if !SD_RAW_SAVE_RAM
    /* the first block is likely to be accessed first, so precache it here */
    raw_block_address = 0xffffffff;
#if SD_RAW_WRITE_BUFFERING
    raw_block_written = 1;
#endif
    if(!sd_raw_read(0, raw_block, sizeof(raw_block)))
        return 0;
#endif

    return 1;
}
Example #3
0
/**
 * \ingroup sd_raw
 * Initializes memory card communication.
 *
 * \returns 0 on failure, 1 on success.
 */
uint8_t sd_raw_init()
{
    /* enable inputs for reading card status */
    configure_pin_available();
    configure_pin_locked();

    /* enable outputs for MOSI, SCK, SS, input for MISO */
    configure_pin_mosi();
    configure_pin_sck();
    configure_pin_ss();
    configure_pin_miso();

    unselect_card();

    /* initialize SPI with lowest frequency; max. 400kHz during identification mode of card */
    S0SPCCR = 150;  /* Set frequency to 400kHz */
    S0SPCR = 0x38;

    /* initialization procedure */
    sd_raw_card_type = 0;
    
    if(!sd_raw_available())
        return 0;

    /* card needs 74 cycles minimum to start up */
    for(uint8_t i = 0; i < 10; ++i)
    {
        /* wait 8 clock cycles */
        sd_raw_rec_byte();
    }

    /* address card */
    select_card();

    /* reset card */
    uint8_t response;
    for(uint16_t i = 0; ; ++i)
    {
        response = sd_raw_send_command(CMD_GO_IDLE_STATE, 0);
        if(response == (1 << R1_IDLE_STATE))
            break;

        if(i == 0x1ff)
        {
            unselect_card();
            return 0;
        }
    }

#if SD_RAW_SDHC
    /* check for version of SD card specification */
    response = sd_raw_send_command(CMD_SEND_IF_COND, 0x100 /* 2.7V - 3.6V */ | 0xaa /* test pattern */);
    if((response & (1 << R1_ILL_COMMAND)) == 0)
    {
        sd_raw_rec_byte();
        sd_raw_rec_byte();
        if((sd_raw_rec_byte() & 0x01) == 0)
            return 0; /* card operation voltage range doesn't match */
        if(sd_raw_rec_byte() != 0xaa)
            return 0; /* wrong test pattern */

        /* card conforms to SD 2 card specification */
        sd_raw_card_type |= (1 << SD_RAW_SPEC_2);
    }
    else
#endif
    {
        /* determine SD/MMC card type */
        sd_raw_send_command(CMD_APP, 0);
        response = sd_raw_send_command(CMD_SD_SEND_OP_COND, 0);
        if((response & (1 << R1_ILL_COMMAND)) == 0)
        {
            /* card conforms to SD 1 card specification */
            sd_raw_card_type |= (1 << SD_RAW_SPEC_1);
        }
        else
        {
            /* MMC card */
        }
    }

    /* wait for card to get ready */
    for(uint16_t i = 0; ; ++i)
    {
        if(sd_raw_card_type & ((1 << SD_RAW_SPEC_1) | (1 << SD_RAW_SPEC_2)))
        {
            uint32_t arg = 0;
#if SD_RAW_SDHC
            if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
                arg = 0x40000000;
#endif
            sd_raw_send_command(CMD_APP, 0);
            response = sd_raw_send_command(CMD_SD_SEND_OP_COND, arg);
        }
        else
        {
            response = sd_raw_send_command(CMD_SEND_OP_COND, 0);
        }

        if((response & (1 << R1_IDLE_STATE)) == 0)
            break;

        if(i == 0x7fff)
        {
            unselect_card();
            return 0;
        }
    }

#if SD_RAW_SDHC
    if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
    {
        if(sd_raw_send_command(CMD_READ_OCR, 0))
        {
            unselect_card();
            return 0;
        }

        if(sd_raw_rec_byte() & 0x40)
            sd_raw_card_type |= (1 << SD_RAW_SPEC_SDHC);

        sd_raw_rec_byte();
        sd_raw_rec_byte();
        sd_raw_rec_byte();
    }
#endif

    /* set block size to 512 bytes */
    if(sd_raw_send_command(CMD_SET_BLOCKLEN, 512))
    {
        unselect_card();
        return 0;
    }

    /* deaddress card */
    unselect_card();

    /* switch to highest SPI frequency possible */
    S0SPCCR = 60; /* ~1MHz-- potentially can be faster */

#if !SD_RAW_SAVE_RAM
    /* the first block is likely to be accessed first, so precache it here */
    raw_block_address = (offset_t) -1;
#if SD_RAW_WRITE_BUFFERING
    raw_block_written = 1;
#endif
    if(!sd_raw_read(0, raw_block, sizeof(raw_block)))
        return 0;
#endif

    return 1;
}
/**
 * \ingroup sd_raw
 * Initializes memory card communication.
 *
 * \returns 0 on failure, 1 on success.
 */
uint8_t sd_raw_init(bool use_crc, uint8_t speed)
{
#if !SD_POOR_DESIGN
    (void)speed;
#endif
#if !SD_RAW_SAVE_RAM
    sd_use_crc = use_crc;
#else
    (void)use_crc;
#endif

    sd_errno = 0;

    /* enable inputs for reading card status */
    configure_pin_available();
    configure_pin_locked();

    /* enable outputs for MOSI, SCK, SS, input for MISO */
    configure_pin_ss();

    /* unselect SS as it may be CS for another SPI device */
    unselect_card();

    configure_pin_mosi();
    configure_pin_sck();
    configure_pin_miso();

    /* initialize SPI with lowest frequency; max. 400kHz during identification mode of card */
    SPCR = (0 << SPIE) | /* SPI Interrupt Enable */
           (1 << SPE)  | /* SPI Enable */
           (0 << DORD) | /* Data Order: MSB first */
           (1 << MSTR) | /* Master mode */
           (0 << CPOL) | /* Clock Polarity: SCK low when idle */
           (0 << CPHA) | /* Clock Phase: sample on rising SCK edge */
           (1 << SPR1) | /* Clock Frequency: f_OSC / 128 */
           (1 << SPR0);
    SPSR = 0; // &= ~(1 << SPI2X); /* No doubled clock frequency */

    /* initialization procedure */
    sd_raw_card_type = 0;
    if(!sd_raw_available())
    {
	sd_errno = SDR_ERR_NOCARD;
        return 0;
    }

    /* card needs 74 cycles minimum to start up with SS/CS high */
    for(uint8_t i = 0; i < 10; ++i)
    {
        /* wait 8 clock cycles */
        sd_raw_rec_byte();
    }

    /* now lower CS */
    select_card();

    /* reset card */
    uint8_t response;
    for(uint16_t i = 0; ; ++i)
    {
        response = sd_raw_send_command(CMD_GO_IDLE_STATE, 0);
        if(response == (1 << R1_IDLE_STATE))
            break;

        if(i == 0x1ff)
        {
            unselect_card();
	    sd_errno = SDR_ERR_COMMS;
            return 0;
        }
    }

#if !SD_RAW_SAVE_RAM
    if ( sd_use_crc ) {
	if ( sd_raw_send_command(CMD_CRC_ON_OFF, 1) != (1 << R1_IDLE_STATE) ) {
	    unselect_card();
	    sd_errno = SDR_ERR_CRC;
	    return 0;
	}
    }
#endif

#if SD_RAW_SDHC
    /* check for version of SD card specification */
    response = sd_raw_send_command(CMD_SEND_IF_COND, 0x100 /* 2.7V - 3.6V */ | 0xaa /* test pattern */);
    if((response & (1 << R1_ILL_COMMAND)) == 0)
    {
        sd_raw_rec_byte();
        sd_raw_rec_byte();
        if((sd_raw_rec_byte() & 0x01) == 0)
	{
	    sd_errno = SDR_ERR_VOLTAGE;
            return 0; /* card operation voltage range doesn't match */
	}
        if(sd_raw_rec_byte() != 0xaa)
	{
	    sd_errno = SDR_ERR_PATTERN;
            return 0; /* wrong test pattern */
	}

        /* card conforms to SD 2 card specification */
        sd_raw_card_type |= (1 << SD_RAW_SPEC_2);
    }
    else
#endif
    {
        /* determine SD/MMC card type */
        sd_raw_send_command(CMD_APP, 0);
        response = sd_raw_send_command(CMD_SD_SEND_OP_COND, 0);
        if((response & (1 << R1_ILL_COMMAND)) == 0)
        {
            /* card conforms to SD 1 card specification */
            sd_raw_card_type |= (1 << SD_RAW_SPEC_1);
        }
        else
        {
            /* MMC card */
        }
    }

    /* wait for card to get ready */
    for(uint16_t i = 0; ; ++i)
    {
        if(sd_raw_card_type & ((1 << SD_RAW_SPEC_1) | (1 << SD_RAW_SPEC_2)))
        {
            uint32_t arg = 0;
#if SD_RAW_SDHC
            if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
                arg = 0x40000000;
#endif
            sd_raw_send_command(CMD_APP, 0);
            response = sd_raw_send_command(CMD_SD_SEND_OP_COND, arg);
        }
        else
        {
            response = sd_raw_send_command(CMD_SEND_OP_COND, 0);
        }

        if((response & (1 << R1_IDLE_STATE)) == 0)
            break;

        if(i == 0x1ff)
        {
            unselect_card();
	    sd_errno = SDR_ERR_COMMS;
            return 0;
        }
    }

#if SD_RAW_SDHC
    if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
    {
        if(sd_raw_send_command(CMD_READ_OCR, 0))
        {
            unselect_card();
	    sd_errno = SDR_ERR_BADRESPONSE;
            return 0;
        }

        if(sd_raw_rec_byte() & 0x40)
            sd_raw_card_type |= (1 << SD_RAW_SPEC_SDHC);

        sd_raw_rec_byte();
        sd_raw_rec_byte();
        sd_raw_rec_byte();
    }
#endif


    /* set block size to 512 bytes */
    if(sd_raw_send_command(CMD_SET_BLOCKLEN, 512))
    {
        unselect_card();
	sd_errno = SDR_ERR_BADRESPONSE;
        return 0;
    }

    /* deaddress card */
    unselect_card();

    /* switch to highest SPI frequency possible */
#if SD_POOR_DESIGN
    switch(speed) {
    /* f_OSC / 2 */
    case 0:
	SPCR &= ~((1 << SPR1) | (1 << SPR0));
	SPSR |= (1 << SPI2X);
	break;

    /* f_OSC / 4 */
    case 1:
	SPCR &= ~((1 << SPR1) | (1 << SPR0));
	SPSR &= ~(1 << SPI2X);
	break;

    /* f_OSC / 8 */
    case 2:
	SPCR |=  (1 << SPR0);
	SPCR &= ~(1 << SPR1);
	SPSR |=  (1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */
	break;

    /* f_OSC / 16 */
    case 3:
	SPCR |=  (1 << SPR0);
	SPCR &= ~(1 << SPR1);
	SPSR &= ~(1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */
	break;

    /* f_OSC / 32 */
    case 4:
	SPCR &= ~(1 << SPR0);
	SPCR |=  (1 << SPR1);
	SPSR |=  (1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */
	break;

	/* f_OSC / 64 [two ways of achieving] */
    case 5:
	SPCR &= ~(1 << SPR0);
	SPCR |= (1 << SPR1);
	SPSR &= ~(1 << SPI2X);
	break;

    /* f_OSC / 128 */
    case 6:
	SPCR |= (1 << SPR1) | (1 << SPR0);
	SPSR &= ~(1 << SPI2X);
	break;

    default:
	sd_errno = SDR_ERR_COMMS;
	return 0;
    }
#else
    // MBI used to use f_OSC / 2
    // But owing to the lousy SD card bus, that doesn't work well
    // Then with the introduction of the revH MightyBoard, they dropped
    // down to f_OSC / 16.

    // / * f_OSC / 2 */
    // SPCR &= ~((1 << SPR1) | (1 << SPR0)); /* Clock Frequency: f_OSC / 4 */
    // SPSR |= (1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */

    /* f_OSC / 16 */
    SPCR |=  ( 1 << SPR0 );
    SPCR &= ~( 1 << SPR1 );
    SPSR &= ~( 1 << SPI2X );

#endif

#if !SD_RAW_SAVE_RAM
    /* the first block is likely to be accessed first, so precache it here */
    raw_block_address = (offset_t) -1;
#if SD_RAW_WRITE_BUFFERING
    raw_block_written = 1;
#endif
    if(!sd_raw_read(0, raw_block, sizeof(raw_block)))
        return 0;
#endif

#if defined(DEBUG_SD)
    sd_errno = SDR_ERR_FOO;
#endif
    // sd_errno set by sd_raw_read
    return 1;
}
/**
 * \ingroup sd_raw
 * Initializes memory card communication.
 *
 * \returns 0 on failure, 1 on success.
 */
uint8_t sd_raw_init(void)
{
	_sd_infodirty = 1;
    /* enable inputs for reading card status */
    configure_pin_available();
    configure_pin_locked();

    /* enable outputs for MOSI, SCK, SS, input for MISO */
    configure_pin_mosi();
    configure_pin_sck();
    configure_pin_ss();
    configure_pin_miso();

    unselect_card();

    /* initialize SPI with lowest frequency; max. 400kHz during identification mode of card */
    SPCR = (0 << SPIE) | /* SPI Interrupt Enable */
           (1 << SPE)  | /* SPI Enable */
           (0 << DORD) | /* Data Order: MSB first */
           (1 << MSTR) | /* Master mode */
           (0 << CPOL) | /* Clock Polarity: SCK low when idle */
           (0 << CPHA) | /* Clock Phase: sample on rising SCK edge */
           (1 << SPR1) | /* Clock Frequency: f_OSC / 128 */
           (1 << SPR0);
    SPSR &= ~(1 << SPI2X); /* No doubled clock frequency */

    /* initialization procedure */
    sd_raw_card_type = 0;
    
    if(!sd_raw_available())
	{
		SD_DEBUG("SD card not available");
        return 0;
	}		

    /* card needs 74 cycles minimum to start up */
	uint16_t i;
    for(i = 0; i < 10; ++i)
    {
        /* wait 8 clock cycles */
        sd_raw_rec_byte();
    }

    /* address card */
    select_card();

    /* reset card */
    uint8_t response;
    for(i = 0; ; ++i)
    {
        response = sd_raw_send_command(CMD_GO_IDLE_STATE, 0);
        if(response == (1 << R1_IDLE_STATE))
            break;

        if(i == 0x1ff)
        {
            unselect_card();
			SD_DEBUG("Some kind of error.");
            return 0;
        }
    }

#if SD_RAW_SDHC
    /* check for version of SD card specification */
    response = sd_raw_send_command(CMD_SEND_IF_COND, 0x100 /* 2.7V - 3.6V */ | 0xaa /* test pattern */);
    if((response & (1 << R1_ILL_COMMAND)) == 0)
    {
        sd_raw_rec_byte();
        sd_raw_rec_byte();
        if((sd_raw_rec_byte() & 0x01) == 0)
		{
			SD_DEBUG("Bad voltage");
            return 0; /* card operation voltage range doesn't match */
		}			
        if(sd_raw_rec_byte() != 0xaa)
		{
			SD_DEBUG("Bad test pattern.");
            return 0; /* wrong test pattern */
		}			

        /* card conforms to SD 2 card specification */
        sd_raw_card_type |= (1 << SD_RAW_SPEC_2);
    }
    else
#endif
    {
        /* determine SD/MMC card type */
        sd_raw_send_command(CMD_APP, 0);
        response = sd_raw_send_command(CMD_SD_SEND_OP_COND, 0);
        if((response & (1 << R1_ILL_COMMAND)) == 0)
        {
            /* card conforms to SD 1 card specification */
            sd_raw_card_type |= (1 << SD_RAW_SPEC_1);
        }
        else
        {
            /* MMC card */
        }
    }

    /* wait for card to get ready */
    for(i = 0; ; ++i)
    {
        if(sd_raw_card_type & ((1 << SD_RAW_SPEC_1) | (1 << SD_RAW_SPEC_2)))
        {
            uint32_t arg = 0;
#if SD_RAW_SDHC
            if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
                arg = 0x40000000;
#endif
            sd_raw_send_command(CMD_APP, 0);
            response = sd_raw_send_command(CMD_SD_SEND_OP_COND, arg);
        }
        else
        {
            response = sd_raw_send_command(CMD_SEND_OP_COND, 0);
        }

        if((response & (1 << R1_IDLE_STATE)) == 0)
            break;

        if(i == 0x7fff)
        {
            unselect_card();
			SD_DEBUG("Some kind of error.");
            return 0;
        }
    }

#if SD_RAW_SDHC
    if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
    {
        if(sd_raw_send_command(CMD_READ_OCR, 0))
        {
            unselect_card();
			SD_DEBUG("Some kind of error.");
            return 0;
        }

        if(sd_raw_rec_byte() & 0x40)
            sd_raw_card_type |= (1 << SD_RAW_SPEC_SDHC);

        sd_raw_rec_byte();
        sd_raw_rec_byte();
        sd_raw_rec_byte();
    }
#endif

    /* set block size to 512 bytes */
    if(sd_raw_send_command(CMD_SET_BLOCKLEN, 512))
    {
        unselect_card();
		SD_DEBUG("Some kind of error.");
        return 0;
    }

    /* deaddress card */
    unselect_card();

    /* switch to highest SPI frequency possible */
    SPCR &= ~((1 << SPR1) | (1 << SPR0)); /* Clock Frequency: f_OSC / 4 */
    SPSR |= (1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */

#if !SD_RAW_SAVE_RAM
    /* the first block is likely to be accessed first, so precache it here */
    raw_block_address = (unsigned long) -1;
#if SD_RAW_WRITE_BUFFERING
    raw_block_written = 1;
#endif
    if(!sd_raw_read(0, raw_block, sizeof(raw_block)))
	{
		SD_DEBUG("Some kind of error.");
        return 0;
	}		
#endif

    return 1;
}
Example #6
0
/**
 * \ingroup sd_raw
 * Initializes memory card communication.
 *
 * \returns 0 on failure, 1 on success.
 */
uint8_t sd_raw_init()
{

	/* Configure Chip-Select Pin*/
    configure_pin_ss();

#if defined(AVRNETIO) && defined(AVRNETIO_ADDON)

	/* enable inputs for reading card status */
	DDRD |= (1<<PD7);
	PORTD |= (1<<PD7);
	DDRD |= (1<<PD5);
	PORTD |= (1<<PD5);
	configure_pin_available();
//    configure_pin_locked();

#elif defined(AVRNETIO) && !defined(AVRNETIO_ADDON)
	
	/* enable inputs for reading card status */
	configure_pin_available();
    configure_pin_locked();
	configure_pin_available_pullup();
	configure_pin_locked_pullup();

#endif

	/* unselect MMC-Card */
    select_card();
    unselect_card();

	/* SPI-Bus Init */
	SPI_init( spi_bus_num );

#if defined(AVRNETIO) && !defined(AVRNETIO_ADDON)
		/* Power up the MMC-Interface */
		configure_power_up();
		power_up();
#endif	
	
    /* initialization procedure */
    sd_raw_card_type = 0;
    
    if(!sd_raw_available())
	{
       return 0;
	}
	
    /* card needs 74 cycles minimum to start up */
    for(uint8_t i = 0; i < 100; ++i)
    {
        /* wait 8 clock cycles */
        sd_raw_rec_byte();
    }

    /* address card */
    select_card();

    /* reset card */
    uint8_t response;
    for(uint16_t i = 0; ; ++i)
    {
        response = sd_raw_send_command(CMD_GO_IDLE_STATE, 0);
        if(response == (1 << R1_IDLE_STATE))
            break;

        if(i == 0xfff)
        {
           unselect_card();
            return 0;
        }
    }


#if SD_RAW_SDHC
    /* check for version of SD card specification */
    response = sd_raw_send_command(CMD_SEND_IF_COND, 0x100 /* 2.7V - 3.6V */ | 0xaa /* test pattern */);
    if((response & (1 << R1_ILL_COMMAND)) == 0)
    {
        sd_raw_rec_byte();
        sd_raw_rec_byte();
        if((sd_raw_rec_byte() & 0x01) == 0)
		{
           unselect_card();
            return 0; /* card operation voltage range doesn't match */
		}
		if(sd_raw_rec_byte() != 0xaa)
		{
           unselect_card();
            return 0; /* wrong test pattern */
		}

        /* card conforms to SD 2 card specification */
        sd_raw_card_type |= (1 << SD_RAW_SPEC_2);
    }
    else
#endif
    {
        /* determine SD/MMC card type */
        sd_raw_send_command(CMD_APP, 0);
        response = sd_raw_send_command(CMD_SD_SEND_OP_COND, 0);
        if((response & (1 << R1_ILL_COMMAND)) == 0)
        {
            /* card conforms to SD 1 card specification */
            sd_raw_card_type |= (1 << SD_RAW_SPEC_1);
        }
        else
        {
            /* MMC card */
        }
    }

    /* wait for card to get ready */
    for(uint16_t i = 0; ; ++i)
    {
        if(sd_raw_card_type & ((1 << SD_RAW_SPEC_1) | (1 << SD_RAW_SPEC_2)))
        {
            uint32_t arg = 0;
#if SD_RAW_SDHC
            if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
                arg = 0x40000000;
#endif
            sd_raw_send_command(CMD_APP, 0);
            response = sd_raw_send_command(CMD_SD_SEND_OP_COND, arg);
        }
        else
        {
            response = sd_raw_send_command(CMD_SEND_OP_COND, 0);
        }

		if((response & (1 << R1_IDLE_STATE)) == 0)
            break;

        if(i == 0x7fff)
        {
           unselect_card();
            return 0;
        }
    }

#if SD_RAW_SDHC
    if(sd_raw_card_type & (1 << SD_RAW_SPEC_2))
    {
        if(sd_raw_send_command(CMD_READ_OCR, 0))
        {
           unselect_card();
            return 0;
        }

        if(sd_raw_rec_byte() & 0x40)
            sd_raw_card_type |= (1 << SD_RAW_SPEC_SDHC);

        sd_raw_rec_byte();
        sd_raw_rec_byte();
        sd_raw_rec_byte();
    }
#endif

    /* set block size to 512 bytes */
    if(sd_raw_send_command(CMD_SET_BLOCKLEN, 512))
    {
        unselect_card();
        return 0;
    }

    /* deaddress card */
    unselect_card();

//    /* switch to highest SPI frequency possible */
//    SPCR &= ~((1 << SPR1) | (1 << SPR0)); /* Clock Frequency: f_OSC / 4 */
//    SPSR |= (1 << SPI2X); /* Doubled Clock Frequency: f_OSC / 2 */

#if !SD_RAW_SAVE_RAM
    /* the first block is likely to be accessed first, so precache it here */
    raw_block_address = (offset_t) -1;
#if SD_RAW_WRITE_BUFFERING
    raw_block_written = 1;
#endif
    if(!sd_raw_read(0, raw_block, sizeof(raw_block)))
    {
       unselect_card();
        return 0;
    }
#endif

   return 1;
}