text: /* Arduino Sd2Card Library
   * Copyright (C) 2009 by William Greiman
   *
   * This file is part of the Arduino Sd2Card Library
   *
   * This Library is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This Library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with the Arduino Sd2Card Library.  If not, see
   * <http://www.gnu.org/licenses/>.
   */
  #define USE_SPI_LIB
  #include <Arduino.h>
  #include "Sd2Card.h"
  //------------------------------------------------------------------------------
  #ifndef SOFTWARE_SPI
  #ifdef USE_SPI_LIB
  #include <SPI.h>
  #ifndef ARDUINO_ARCH_SAMD
  static SPISettings settings;
  #endif
  #endif
  // functions for hardware SPI
  /** Send a byte to the card */
  static void spiSend(uint8_t b) {
  #ifndef USE_SPI_LIB
    SPDR = b;
    while (!(SPSR & (1 << SPIF)))
      ;
  #else
    SPI.transfer(b);
  #endif
  }
  /** Receive a byte from the card */
  static  uint8_t spiRec(void) {
  #ifndef USE_SPI_LIB
    spiSend(0XFF);
    return SPDR;
  #else
    return SPI.transfer(0xFF);
  #endif
  }
  #else  // SOFTWARE_SPI
  //------------------------------------------------------------------------------
  /** nop to tune soft SPI timing */
  #define nop asm volatile ("nop\n\t")
  //------------------------------------------------------------------------------
  /** Soft SPI receive */
  uint8_t spiRec(void) {
    uint8_t data = 0;
    // no interrupts during byte receive - about 8 us
    cli();
    // output pin high - like sending 0XFF
    fastDigitalWrite(SPI_MOSI_PIN, HIGH);
  
    for (uint8_t i = 0; i < 8; i++) {
      fastDigitalWrite(SPI_SCK_PIN, HIGH);
  
      // adjust so SCK is nice
      nop;
      nop;
  
      data <<= 1;
  
      if (fastDigitalRead(SPI_MISO_PIN)) data |= 1;
  
      fastDigitalWrite(SPI_SCK_PIN, LOW);
    }
    // enable interrupts
    sei();
    return data;
  }
  //------------------------------------------------------------------------------
  /** Soft SPI send */
  void spiSend(uint8_t data) {
    // no interrupts during byte send - about 8 us
    cli();
    for (uint8_t i = 0; i < 8; i++) {
      fastDigitalWrite(SPI_SCK_PIN, LOW);
  
      fastDigitalWrite(SPI_MOSI_PIN, data & 0X80);
  
      data <<= 1;
  
      fastDigitalWrite(SPI_SCK_PIN, HIGH);
    }
    // hold SCK high for a few ns
    nop;
    nop;
    nop;
    nop;
  
    fastDigitalWrite(SPI_SCK_PIN, LOW);
    // enable interrupts
    sei();
  }
  #endif  // SOFTWARE_SPI
  //------------------------------------------------------------------------------
  // send command and return error code.  Return zero for OK
  uint8_t Sd2Card::cardCommand(uint8_t cmd, uint32_t arg) {
    // end read if in partialBlockRead mode
    readEnd();
  
    // select card
    chipSelectLow();
  
    // wait up to 300 ms if busy
    waitNotBusy(300);
  
    // send command
    spiSend(cmd | 0x40);
  
    // send argument
    for (int8_t s = 24; s >= 0; s -= 8) spiSend(arg >> s);
  
    // send CRC
    uint8_t crc = 0XFF;
    if (cmd == CMD0) crc = 0X95;  // correct crc for CMD0 with arg 0
    if (cmd == CMD8) crc = 0X87;  // correct crc for CMD8 with arg 0X1AA
    spiSend(crc);
  
    // wait for response
    for (uint8_t i = 0; ((status_ = spiRec()) & 0X80) && i != 0XFF; i++)
      ;
    return status_;
  }
  //------------------------------------------------------------------------------
  /**
   * Determine the size of an SD flash memory card.
   *
   * \return The number of 512 byte data blocks in the card
   *         or zero if an error occurs.
   */
  uint32_t Sd2Card::cardSize(void) {
    csd_t csd;
    if (!readCSD(&csd)) return 0;
    if (csd.v1.csd_ver == 0) {
      uint8_t read_bl_len = csd.v1.read_bl_len;
      uint16_t c_size = (csd.v1.c_size_high << 10)
                        | (csd.v1.c_size_mid << 2) | csd.v1.c_size_low;
      uint8_t c_size_mult = (csd.v1.c_size_mult_high << 1)
                            | csd.v1.c_size_mult_low;
      return (uint32_t)(c_size + 1) << (c_size_mult + read_bl_len - 7);
    } else if (csd.v2.csd_ver == 1) {
      uint32_t c_size = ((uint32_t)csd.v2.c_size_high << 16)
                        | (csd.v2.c_size_mid << 8) | csd.v2.c_size_low;
      return (c_size + 1) << 10;
    } else {
      error(SD_CARD_ERROR_BAD_CSD);
      return 0;
    }
  }
  //------------------------------------------------------------------------------
  static uint8_t chip_select_asserted = 0;
  
  void Sd2Card::chipSelectHigh(void) {
    digitalWrite(chipSelectPin_, HIGH);
  #ifdef USE_SPI_LIB
    if (chip_select_asserted) {
      chip_select_asserted = 0;
  	#ifndef ARDUINO_ARCH_SAMD
      SPI.endTransaction();
  	#endif
    }
  #endif
  }
  //------------------------------------------------------------------------------
  void Sd2Card::chipSelectLow(void) {
  #ifdef USE_SPI_LIB
    if (!chip_select_asserted) {
      chip_select_asserted = 1;
  	#ifndef ARDUINO_ARCH_SAMD
      SPI.beginTransaction(settings);
  	#endif
    }
  #endif
    digitalWrite(chipSelectPin_, LOW);
  }
  //------------------------------------------------------------------------------
  /** Erase a range of blocks.
   *
   * \param[in] firstBlock The address of the first block in the range.
   * \param[in] lastBlock The address of the last block in the range.
   *
   * \note This function requests the SD card to do a flash erase for a
   * range of blocks.  The data on the card after an erase operation is
   * either 0 or 1, depends on the card vendor.  The card must support
   * single block erase.
   *
   * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.
   */
  uint8_t Sd2Card::erase(uint32_t firstBlock, uint32_t lastBlock) {
    if (!eraseSingleBlockEnable()) {
      error(SD_CARD_ERROR_ERASE_SINGLE_BLOCK);
      goto fail;
    }
    if (type_ != SD_CARD_TYPE_SDHC) {
      firstBlock <<= 9;
      lastBlock <<= 9;
    }
    if (cardCommand(CMD32, firstBlock)
      || cardCommand(CMD33, lastBlock)
      || cardCommand(CMD38, 0)) {
        error(SD_CARD_ERROR_ERASE);
        goto fail;
    }
    if (!waitNotBusy(SD_ERASE_TIMEOUT)) {
      error(SD_CARD_ERROR_ERASE_TIMEOUT);
      goto fail;
    }
    chipSelectHigh();
    return true;
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /** Determine if card supports single block erase.
   *
   * \return The value one, true, is returned if single block erase is supported.
   * The value zero, false, is returned if single block erase is not supported.
   */
  uint8_t Sd2Card::eraseSingleBlockEnable(void) {
    csd_t csd;
    return readCSD(&csd) ? csd.v1.erase_blk_en : 0;
  }
  //------------------------------------------------------------------------------
  /**
   * Initialize an SD flash memory card.
   *
   * \param[in] sckRateID SPI clock rate selector. See setSckRate().
   * \param[in] chipSelectPin SD chip select pin number.
   *
   * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.  The reason for failure
   * can be determined by calling errorCode() and errorData().
   */
  uint8_t Sd2Card::init(uint8_t sckRateID, uint8_t chipSelectPin) {
  	
    errorCode_ = inBlock_ = partialBlockRead_ = type_ = 0;
    chipSelectPin_ = chipSelectPin;
    // 16-bit init start time allows over a minute
    uint16_t t0 = (uint16_t)millis();
    uint32_t arg;
  
    // set pin modes
    pinMode(chipSelectPin_, OUTPUT);
    digitalWrite(chipSelectPin_, HIGH);
  #ifndef USE_SPI_LIB
    pinMode(SPI_MISO_PIN, INPUT);
    pinMode(SPI_MOSI_PIN, OUTPUT);
    pinMode(SPI_SCK_PIN, OUTPUT);
  #endif
  
  #ifndef SOFTWARE_SPI
  #ifndef USE_SPI_LIB
    // SS must be in output mode even it is not chip select
    pinMode(SS_PIN, OUTPUT);
    digitalWrite(SS_PIN, HIGH); // disable any SPI device using hardware SS pin
    // Enable SPI, Master, clock rate f_osc/128
    SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR1) | (1 << SPR0);
    // clear double speed
    SPSR &= ~(1 << SPI2X);
  #else // USE_SPI_LIB
    SPI.begin();
    #ifndef ARDUINO_ARCH_SAMD
    settings = SPISettings(250000, MSBFIRST, SPI_MODE0);
    #endif
  #endif // USE_SPI_LIB
  #endif // SOFTWARE_SPI
  
    // must supply min of 74 clock cycles with CS high.
  #ifdef USE_SPI_LIB
  #ifndef ARDUINO_ARCH_SAMD
    SPI.beginTransaction(settings);
  #endif
  #endif
    for (uint8_t i = 0; i < 10; i++) spiSend(0XFF);
  #ifdef USE_SPI_LIB  
  #ifndef ARDUINO_ARCH_SAMD
    SPI.endTransaction();
  #endif
  #endif
  
    chipSelectLow();
  
    // command to go idle in SPI mode
    while ((status_ = cardCommand(CMD0, 0)) != R1_IDLE_STATE) {
      if (((uint16_t)millis() - t0) > SD_INIT_TIMEOUT) {
        error(SD_CARD_ERROR_CMD0);
        goto fail;
      }
    }
    // check SD version
    if ((cardCommand(CMD8, 0x1AA) & R1_ILLEGAL_COMMAND)) {
      type(SD_CARD_TYPE_SD1);
    } else {
      // only need last byte of r7 response
      for (uint8_t i = 0; i < 4; i++) status_ = spiRec();
      if (status_ != 0XAA) {
        error(SD_CARD_ERROR_CMD8);
        goto fail;
      }
      type(SD_CARD_TYPE_SD2);
    }
    // initialize card and send host supports SDHC if SD2
    arg = type() == SD_CARD_TYPE_SD2 ? 0X40000000 : 0;
  
    while ((status_ = cardAcmd(ACMD41, arg)) != R1_READY_STATE) {
      // check for timeout
      if (((uint16_t)millis() - t0) > SD_INIT_TIMEOUT) {
        error(SD_CARD_ERROR_ACMD41);
        goto fail;
      }
    }
    // if SD2 read OCR register to check for SDHC card
    if (type() == SD_CARD_TYPE_SD2) {
      if (cardCommand(CMD58, 0)) {
        error(SD_CARD_ERROR_CMD58);
        goto fail;
      }
      if ((spiRec() & 0XC0) == 0XC0) type(SD_CARD_TYPE_SDHC);
      // discard rest of ocr - contains allowed voltage range
      for (uint8_t i = 0; i < 3; i++) spiRec();
    }
    chipSelectHigh();
  
  #ifndef SOFTWARE_SPI
    return setSckRate(sckRateID);
  #else  // SOFTWARE_SPI
    return true;
  #endif  // SOFTWARE_SPI
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /**
   * Enable or disable partial block reads.
   *
   * Enabling partial block reads improves performance by allowing a block
   * to be read over the SPI bus as several sub-blocks.  Errors may occur
   * if the time between reads is too long since the SD card may timeout.
   * The SPI SS line will be held low until the entire block is read or
   * readEnd() is called.
   *
   * Use this for applications like the Adafruit Wave Shield.
   *
   * \param[in] value The value TRUE (non-zero) or FALSE (zero).)
   */
  void Sd2Card::partialBlockRead(uint8_t value) {
    readEnd();
    partialBlockRead_ = value;
  }
  //------------------------------------------------------------------------------
  /**
   * Read a 512 byte block from an SD card device.
   *
   * \param[in] block Logical block to be read.
   * \param[out] dst Pointer to the location that will receive the data.
  
   * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.
   */
  uint8_t Sd2Card::readBlock(uint32_t block, uint8_t* dst) {
    return readData(block, 0, 512, dst);
  }
  //------------------------------------------------------------------------------
  /**
   * Read part of a 512 byte block from an SD card.
   *
   * \param[in] block Logical block to be read.
   * \param[in] offset Number of bytes to skip at start of block
   * \param[out] dst Pointer to the location that will receive the data.
   * \param[in] count Number of bytes to read
   * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.
   */
  uint8_t Sd2Card::readData(uint32_t block,
          uint16_t offset, uint16_t count, uint8_t* dst) {
    uint16_t n;
    if (count == 0) return true;
    if ((count + offset) > 512) {
      goto fail;
    }
    if (!inBlock_ || block != block_ || offset < offset_) {
      block_ = block;
      // use address if not SDHC card
      if (type()!= SD_CARD_TYPE_SDHC) block <<= 9;
      if (cardCommand(CMD17, block)) {
        error(SD_CARD_ERROR_CMD17);
        goto fail;
      }
      if (!waitStartBlock()) {
        goto fail;
      }
      offset_ = 0;
      inBlock_ = 1;
    }
  
  #ifdef OPTIMIZE_HARDWARE_SPI
    // start first spi transfer
    SPDR = 0XFF;
  
    // skip data before offset
    for (;offset_ < offset; offset_++) {
      while (!(SPSR & (1 << SPIF)))
        ;
      SPDR = 0XFF;
    }
    // transfer data
    n = count - 1;
    for (uint16_t i = 0; i < n; i++) {
      while (!(SPSR & (1 << SPIF)))
        ;
      dst[i] = SPDR;
      SPDR = 0XFF;
    }
    // wait for last byte
    while (!(SPSR & (1 << SPIF)))
      ;
    dst[n] = SPDR;
  
  #else  // OPTIMIZE_HARDWARE_SPI
  
    // skip data before offset
    for (;offset_ < offset; offset_++) {
      spiRec();
    }
    // transfer data
    for (uint16_t i = 0; i < count; i++) {
      dst[i] = spiRec();
    }
  #endif  // OPTIMIZE_HARDWARE_SPI
  
    offset_ += count;
    if (!partialBlockRead_ || offset_ >= 512) {
      // read rest of data, checksum and set chip select high
      readEnd();
    }
    return true;
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /** Skip remaining data in a block when in partial block read mode. */
  void Sd2Card::readEnd(void) {
    if (inBlock_) {
        // skip data and crc
  #ifdef OPTIMIZE_HARDWARE_SPI
      // optimize skip for hardware
      SPDR = 0XFF;
      while (offset_++ < 513) {
        while (!(SPSR & (1 << SPIF)))
          ;
        SPDR = 0XFF;
      }
      // wait for last crc byte
      while (!(SPSR & (1 << SPIF)))
        ;
  #else  // OPTIMIZE_HARDWARE_SPI
      while (offset_++ < 514) spiRec();
  #endif  // OPTIMIZE_HARDWARE_SPI
      chipSelectHigh();
      inBlock_ = 0;
    }
  }
  //------------------------------------------------------------------------------
  /** read CID or CSR register */
  uint8_t Sd2Card::readRegister(uint8_t cmd, void* buf) {
    uint8_t* dst = reinterpret_cast<uint8_t*>(buf);
    if (cardCommand(cmd, 0)) {
      error(SD_CARD_ERROR_READ_REG);
      goto fail;
    }
    if (!waitStartBlock()) goto fail;
    // transfer data
    for (uint16_t i = 0; i < 16; i++) dst[i] = spiRec();
    spiRec();  // get first crc byte
    spiRec();  // get second crc byte
    chipSelectHigh();
    return true;
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /**
   * Set the SPI clock rate.
   *
   * \param[in] sckRateID A value in the range [0, 6].
   *
   * The SPI clock will be set to F_CPU/pow(2, 1 + sckRateID). The maximum
   * SPI rate is F_CPU/2 for \a sckRateID = 0 and the minimum rate is F_CPU/128
   * for \a scsRateID = 6.
   *
   * \return The value one, true, is returned for success and the value zero,
   * false, is returned for an invalid value of \a sckRateID.
   */
  uint8_t Sd2Card::setSckRate(uint8_t sckRateID) {
    if (sckRateID > 6) {
      error(SD_CARD_ERROR_SCK_RATE);
      return false;
    }
  #ifndef USE_SPI_LIB
    // see avr processor datasheet for SPI register bit definitions
    if ((sckRateID & 1) || sckRateID == 6) {
      SPSR &= ~(1 << SPI2X);
    } else {
      SPSR |= (1 << SPI2X);
    }
    SPCR &= ~((1 <<SPR1) | (1 << SPR0));
    SPCR |= (sckRateID & 4 ? (1 << SPR1) : 0)
      | (sckRateID & 2 ? (1 << SPR0) : 0);
  #else // USE_SPI_LIB
    #if defined(ARDUINO_ARCH_SAM)
    switch (sckRateID) {
      case 0:  settings = SPISettings(25000000, MSBFIRST, SPI_MODE0); break;
      case 1:  settings = SPISettings(4000000, MSBFIRST, SPI_MODE0); break;
      case 2:  settings = SPISettings(2000000, MSBFIRST, SPI_MODE0); break;
      case 3:  settings = SPISettings(1000000, MSBFIRST, SPI_MODE0); break;
      case 4:  settings = SPISettings(500000, MSBFIRST, SPI_MODE0); break;
      case 5:  settings = SPISettings(250000, MSBFIRST, SPI_MODE0); break;
      default: settings = SPISettings(125000, MSBFIRST, SPI_MODE0);
    }
    #endif
  #endif // USE_SPI_LIB
    return true;
  }
  //------------------------------------------------------------------------------
  // wait for card to go not busy
  uint8_t Sd2Card::waitNotBusy(uint16_t timeoutMillis) {
    uint16_t t0 = millis();
    do {
      if (spiRec() == 0XFF) return true;
    }
    while (((uint16_t)millis() - t0) < timeoutMillis);
    return false;
  }
  //------------------------------------------------------------------------------
  /** Wait for start block token */
  uint8_t Sd2Card::waitStartBlock(void) {
    uint16_t t0 = millis();
    while ((status_ = spiRec()) == 0XFF) {
      if (((uint16_t)millis() - t0) > SD_READ_TIMEOUT) {
        error(SD_CARD_ERROR_READ_TIMEOUT);
        goto fail;
      }
    }
    if (status_ != DATA_START_BLOCK) {
      error(SD_CARD_ERROR_READ);
      goto fail;
    }
    return true;
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /**
   * Writes a 512 byte block to an SD card.
   *
   * \param[in] blockNumber Logical block to be written.
   * \param[in] src Pointer to the location of the data to be written.
   * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.
   */
  uint8_t Sd2Card::writeBlock(uint32_t blockNumber, const uint8_t* src) {
  #if SD_PROTECT_BLOCK_ZERO
    // don't allow write to first block
    if (blockNumber == 0) {
      error(SD_CARD_ERROR_WRITE_BLOCK_ZERO);
      goto fail;
    }
  #endif  // SD_PROTECT_BLOCK_ZERO
  
    // use address if not SDHC card
    if (type() != SD_CARD_TYPE_SDHC) blockNumber <<= 9;
    if (cardCommand(CMD24, blockNumber)) {
      error(SD_CARD_ERROR_CMD24);
      goto fail;
    }
    if (!writeData(DATA_START_BLOCK, src)) goto fail;
  
    // wait for flash programming to complete
    if (!waitNotBusy(SD_WRITE_TIMEOUT)) {
      error(SD_CARD_ERROR_WRITE_TIMEOUT);
      goto fail;
    }
    // response is r2 so get and check two bytes for nonzero
    if (cardCommand(CMD13, 0) || spiRec()) {
      error(SD_CARD_ERROR_WRITE_PROGRAMMING);
      goto fail;
    }
    chipSelectHigh();
    return true;
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /** Write one data block in a multiple block write sequence */
  uint8_t Sd2Card::writeData(const uint8_t* src) {
    // wait for previous write to finish
    if (!waitNotBusy(SD_WRITE_TIMEOUT)) {
      error(SD_CARD_ERROR_WRITE_MULTIPLE);
      chipSelectHigh();
      return false;
    }
    return writeData(WRITE_MULTIPLE_TOKEN, src);
  }
  //------------------------------------------------------------------------------
  // send one block of data for write block or write multiple blocks
  uint8_t Sd2Card::writeData(uint8_t token, const uint8_t* src) {
  #ifdef OPTIMIZE_HARDWARE_SPI
  
    // send data - optimized loop
    SPDR = token;
  
    // send two byte per iteration
    for (uint16_t i = 0; i < 512; i += 2) {
      while (!(SPSR & (1 << SPIF)))
        ;
      SPDR = src[i];
      while (!(SPSR & (1 << SPIF)))
        ;
      SPDR = src[i+1];
    }
  
    // wait for last data byte
    while (!(SPSR & (1 << SPIF)))
      ;
  
  #else  // OPTIMIZE_HARDWARE_SPI
    spiSend(token);
    for (uint16_t i = 0; i < 512; i++) {
      spiSend(src[i]);
    }
  #endif  // OPTIMIZE_HARDWARE_SPI
    spiSend(0xff);  // dummy crc
    spiSend(0xff);  // dummy crc
  
    status_ = spiRec();
    if ((status_ & DATA_RES_MASK) != DATA_RES_ACCEPTED) {
      error(SD_CARD_ERROR_WRITE);
      chipSelectHigh();
      return false;
    }
    return true;
  }
  //------------------------------------------------------------------------------
  /** Start a write multiple blocks sequence.
   *
   * \param[in] blockNumber Address of first block in sequence.
   * \param[in] eraseCount The number of blocks to be pre-erased.
   *
   * \note This function is used with writeData() and writeStop()
   * for optimized multiple block writes.
   *
   * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.
   */
  uint8_t Sd2Card::writeStart(uint32_t blockNumber, uint32_t eraseCount) {
  #if SD_PROTECT_BLOCK_ZERO
    // don't allow write to first block
    if (blockNumber == 0) {
      error(SD_CARD_ERROR_WRITE_BLOCK_ZERO);
      goto fail;
    }
  #endif  // SD_PROTECT_BLOCK_ZERO
    // send pre-erase count
    if (cardAcmd(ACMD23, eraseCount)) {
      error(SD_CARD_ERROR_ACMD23);
      goto fail;
    }
    // use address if not SDHC card
    if (type() != SD_CARD_TYPE_SDHC) blockNumber <<= 9;
    if (cardCommand(CMD25, blockNumber)) {
      error(SD_CARD_ERROR_CMD25);
      goto fail;
    }
    return true;
  
   fail:
    chipSelectHigh();
    return false;
  }
  //------------------------------------------------------------------------------
  /** End a write multiple blocks sequence.
   *
  * \return The value one, true, is returned for success and
   * the value zero, false, is returned for failure.
   */
  uint8_t Sd2Card::writeStop(void) {
    if (!waitNotBusy(SD_WRITE_TIMEOUT)) goto fail;
    spiSend(STOP_TRAN_TOKEN);
    if (!waitNotBusy(SD_WRITE_TIMEOUT)) goto fail;
    chipSelectHigh();
    return true;
  
   fail:
    error(SD_CARD_ERROR_STOP_TRAN);
    chipSelectHigh();
    return false;
  }
  