text: /**
   * Copyright (c) 2011-2018 Bill Greiman
   * This file is part of the SdFat library for SD memory cards.
   *
   * MIT License
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  /**
   * \file
   * \brief SpiDriver classes
   */
  #ifndef SdSpiDriver_h
  #define SdSpiDriver_h
  #include <Arduino.h>
  #include "SdSpiBaseDriver.h"
  #include "SoftwareSPI.h"
  #include "SPI.h"
  #include "SdFatConfig.h"
  
  //------------------------------------------------------------------------------
  /** SDCARD_SPI is defined if board has built-in SD card socket */
  #ifndef SDCARD_SPI
  #define SDCARD_SPI swSPI
  typedef SoftwareSPIClass SDCARD_Class;
  #endif  // SDCARD_SPI
  //------------------------------------------------------------------------------
  /**
   * \class SdSpiLibDriver
   * \brief SdSpiLibDriver - use standard SPI library.
   */
  #if ENABLE_SOFTWARE_SPI_CLASS
  class SdSpiLibDriver : public SdSpiBaseDriver {
  #else  // ENABLE_SOFTWARE_SPI_CLASS
  class SdSpiLibDriver {
  #endif  // ENABLE_SOFTWARE_SPI_CLASS
   public:
  #if IMPLEMENT_SPI_PORT_SELECTION
    /** Activate SPI hardware. */
    void activate() {
      m_spi->beginTransaction(m_spiSettings);
    }
    /** Deactivate SPI hardware. */
    void deactivate() {
      m_spi->endTransaction();
    }
    /** Initialize the SPI bus.
     *
     * \param[in] csPin SD card chip select pin.
     */
    void begin(uint8_t csPin) {
      m_csPin = csPin;
      digitalWrite(csPin, HIGH);
      pinMode(csPin, OUTPUT);
      m_spi->begin();
    }
    /** Receive a byte.
     *
     * \return The byte.
     */
    uint8_t receive() {
      return m_spi->transfer( 0XFF);
    }
    /** Receive multiple bytes.
    *
    * \param[out] buf Buffer to receive the data.
    * \param[in] n Number of bytes to receive.
    *
    * \return Zero for no error or nonzero error code.
    */
    uint8_t receive(uint8_t* buf, size_t n) {
      for (size_t i = 0; i < n; i++) {
        buf[i] = m_spi->transfer(0XFF);
      }
      return 0;
    }
    /** Send a byte.
     *
     * \param[in] data Byte to send
     */
    void send(uint8_t data) {
      m_spi->transfer(data);
    }
    /** Send multiple bytes.
     *
     * \param[in] buf Buffer for data to be sent.
     * \param[in] n Number of bytes to send.
     */
    void send(const uint8_t* buf, size_t n) {
      for (size_t i = 0; i < n; i++) {
        m_spi->transfer(buf[i]);
      }
    }
  #else  // IMPLEMENT_SPI_PORT_SELECTION
    /** Activate SPI hardware. */
    void activate() {
      SDCARD_SPI.beginTransaction(m_spiSettings);
    }
    /** Deactivate SPI hardware. */
    void deactivate() {
      SDCARD_SPI.endTransaction();
    }
    /** Initialize the SPI bus.
     *
     * \param[in] csPin SD card chip select pin.
     */
    void begin(uint8_t csPin) {
      m_csPin = csPin;
      digitalWrite(csPin, HIGH);
      pinMode(csPin, OUTPUT);
      SDCARD_SPI.begin();
    }
    /** Receive a byte.
     *
     * \return The byte.
     */
    uint8_t receive() {
      return SDCARD_SPI.transfer( 0XFF);
    }
    /** Receive multiple bytes.
    *
    * \param[out] buf Buffer to receive the data.
    * \param[in] n Number of bytes to receive.
    *
    * \return Zero for no error or nonzero error code.
    */
    uint8_t receive(uint8_t* buf, size_t n) {
      for (size_t i = 0; i < n; i++) {
        buf[i] = SDCARD_SPI.transfer(0XFF);
      }
      return 0;
    }
    /** Send a byte.
     *
     * \param[in] data Byte to send
     */
    void send(uint8_t data) {
      SDCARD_SPI.transfer(data);
    }
    /** Send multiple bytes.
     *
     * \param[in] buf Buffer for data to be sent.
     * \param[in] n Number of bytes to send.
     */
    void send(const uint8_t* buf, size_t n) {
      for (size_t i = 0; i < n; i++) {
        SDCARD_SPI.transfer(buf[i]);
      }
    }
  #endif  // IMPLEMENT_SPI_PORT_SELECTION
    /** Set CS low. */
    void select() {
      digitalWrite(m_csPin, LOW);
    }
    /** Save SPISettings.
     *
     * \param[in] spiSettings SPI speed, mode, and byte order.
     */
    void setSpiSettings(SPISettings spiSettings) {
      m_spiSettings = spiSettings;
    }
    /** Set CS high. */
    void unselect() {
      digitalWrite(m_csPin, HIGH);
    }
  #if IMPLEMENT_SPI_PORT_SELECTION || defined(DOXYGEN)
    /** Set SPI port.
     * \param[in] spiPort Hardware SPI port.
     */
    void setPort(SDCARD_Class* spiPort) {
      m_spi = spiPort ? spiPort : &SDCARD_SPI;
    }
   private:
    SDCARD_Class* m_spi;
  #else   // IMPLEMENT_SPI_PORT_SELECTION
   private:
  #endif  // IMPLEMENT_SPI_PORT_SELECTION
    SPISettings m_spiSettings;
    uint8_t m_csPin;
  };
  //------------------------------------------------------------------------------
  /**
   * \class SdSpiAltDriver
   * \brief Optimized SPI class for access to SD and SDHC flash memory cards.
   */
  #if ENABLE_SOFTWARE_SPI_CLASS
  class SdSpiAltDriver : public SdSpiBaseDriver {
  #else  // ENABLE_SOFTWARE_SPI_CLASS
  class SdSpiAltDriver {
  #endif  // ENABLE_SOFTWARE_SPI_CLASS
   public:
    /** Activate SPI hardware. */
    void activate();
    /** Deactivate SPI hardware. */
    void deactivate();
    /** Initialize the SPI bus.
     *
     * \param[in] csPin SD card chip select pin.
     */
    void begin(uint8_t csPin);
    /** Receive a byte.
     *
     * \return The byte.
     */
    uint8_t receive();
    /** Receive multiple bytes.
    *
    * \param[out] buf Buffer to receive the data.
    * \param[in] n Number of bytes to receive.
    *
    * \return Zero for no error or nonzero error code.
    */
    uint8_t receive(uint8_t* buf, size_t n);
    /** Send a byte.
     *
     * \param[in] data Byte to send
     */
    void send(uint8_t data);
    /** Send multiple bytes.
     *
     * \param[in] buf Buffer for data to be sent.
     * \param[in] n Number of bytes to send.
     */
    void send(const uint8_t* buf, size_t n);
    /** Set CS low. */
    void select() {
       digitalWrite(m_csPin, LOW);
    }
    /** Save SPISettings.
     *
     * \param[in] spiSettings SPI speed, mode, and byte order.
     */
    void setSpiSettings(SPISettings spiSettings) {
      m_spiSettings = spiSettings;
    }
    /** Set CS high. */
    void unselect() {
      digitalWrite(m_csPin, HIGH);
    }
  #if IMPLEMENT_SPI_PORT_SELECTION || defined(DOXYGEN)
    /** Set SPI port number.
     * \param[in] spiPort Hardware SPI port.
     */
    void setPort(SDCARD_Class* spiPort) {
      m_spi = spiPort ? spiPort : &SDCARD_SPI;
    }
   private:
    SDCARD_Class* m_spi;
  #else   // IMPLEMENT_SPI_PORT_SELECTION
   private:
  #endif  // IMPLEMENT_SPI_PORT_SELECTION
    SPISettings m_spiSettings;
    uint8_t m_csPin;
  };
  //------------------------------------------------------------------------------
  #if ENABLE_SOFTWARE_SPI_CLASS || defined(DOXYGEN)
  #ifdef ARDUINO
  #include "SoftSPI.h"
  #elif defined(PLATFORM_ID)  // Only defined if a Particle device
  #include "SoftSPIParticle.h"
  #endif  // ARDUINO
  /**
   * \class SdSpiSoftDriver
   * \brief Software SPI class for access to SD and SDHC flash memory cards.
   */
  template<uint8_t MisoPin, uint8_t MosiPin, uint8_t SckPin>
  class SdSpiSoftDriver : public SdSpiBaseDriver {
   public:
    /** Dummy activate SPI hardware for software SPI */
    void activate() {}
    /** Dummy deactivate SPI hardware for software SPI */
    void deactivate() {}
    /** Initialize the SPI bus.
     *
     * \param[in] csPin SD card chip select pin.
     */
    void begin(uint8_t csPin) {
      m_csPin = csPin;
      pinMode(m_csPin, OUTPUT);
      digitalWrite(m_csPin, HIGH);
      m_spi.begin();
    }
    /** Receive a byte.
     *
     * \return The byte.
     */
    uint8_t receive() {
      return m_spi.receive();
    }
    /** Receive multiple bytes.
    *
    * \param[out] buf Buffer to receive the data.
    * \param[in] n Number of bytes to receive.
    *
    * \return Zero for no error or nonzero error code.
    */
    uint8_t receive(uint8_t* buf, size_t n) {
      for (size_t i = 0; i < n; i++) {
        buf[i] = receive();
      }
      return 0;
    }
    /** Send a byte.
     *
     * \param[in] data Byte to send
     */
    void send(uint8_t data) {
      m_spi.send(data);
    }
    /** Send multiple bytes.
     *
     * \param[in] buf Buffer for data to be sent.
     * \param[in] n Number of bytes to send.
     */
    void send(const uint8_t* buf , size_t n) {
      for (size_t i = 0; i < n; i++) {
        send(buf[i]);
      }
    }
    /** Set CS low. */
    void select() {
       digitalWrite(m_csPin, LOW);
    }
    /** Save SPISettings.
     *
     * \param[in] spiSettings SPI speed, mode, and byte order.
     */
    void setSpiSettings(SPISettings spiSettings) {
      (void)spiSettings;
    }
    /** Set CS high. */
    void unselect() {
      digitalWrite(m_csPin, HIGH);
    }
  
   private:
    uint8_t m_csPin;
    SoftSPI<MisoPin, MosiPin, SckPin, 0> m_spi;
  };
  #endif  // ENABLE_SOFTWARE_SPI_CLASS || defined(DOXYGEN)
  //------------------------------------------------------------------------------
  // Choose SPI driver for SdFat and SdFatEX classes.
  #if USE_STANDARD_SPI_LIBRARY || !SD_HAS_CUSTOM_SPI
  /** SdFat uses Arduino library SPI. */
  typedef SdSpiLibDriver SdFatSpiDriver;
  #else  // USE_STANDARD_SPI_LIBRARY || !SD_HAS_CUSTOM_SPI
  /** SdFat uses custom fast SPI. */
  typedef SdSpiAltDriver SdFatSpiDriver;
  #endif  // USE_STANDARD_SPI_LIBRARY || !SD_HAS_CUSTOM_SPI
  
  /** typedef for for SdSpiCard class. */
  #if ENABLE_SOFTWARE_SPI_CLASS
  // Need virtual driver.
  typedef SdSpiBaseDriver SdSpiDriver;
  #else  // ENABLE_SOFTWARE_SPI_CLASS
  // Don't need virtual driver.
  typedef SdFatSpiDriver SdSpiDriver;
  #endif  // ENABLE_SOFTWARE_SPI_CLASS
  //==============================================================================
  // Use of in-line for AVR to save flash.
  #ifdef __AVR__
  //------------------------------------------------------------------------------
  inline void SdSpiAltDriver::begin(uint8_t csPin) {
    m_csPin = csPin;
    pinMode(m_csPin, OUTPUT);
    digitalWrite(m_csPin, HIGH);
    SPI.begin();
  }
  //------------------------------------------------------------------------------
  inline void SdSpiAltDriver::activate() {
    SPI.beginTransaction(m_spiSettings);
  }
  //------------------------------------------------------------------------------
  inline void SdSpiAltDriver::deactivate() {
    SPI.endTransaction();
  }
  //------------------------------------------------------------------------------
  inline uint8_t SdSpiAltDriver::receive() {
    SPDR = 0XFF;
    while (!(SPSR & (1 << SPIF))) {}
    return SPDR;
  }
  //------------------------------------------------------------------------------
  inline uint8_t SdSpiAltDriver::receive(uint8_t* buf, size_t n) {
    if (n-- == 0) {
      return 0;
    }
    SPDR = 0XFF;
    for (size_t i = 0; i < n; i++) {
      while (!(SPSR & (1 << SPIF))) {}
      uint8_t b = SPDR;
      SPDR = 0XFF;
      buf[i] = b;
    }
    while (!(SPSR & (1 << SPIF))) {}
    buf[n] = SPDR;
    return 0;
  }
  //------------------------------------------------------------------------------
  inline void SdSpiAltDriver::send(uint8_t data) {
    SPDR = data;
    while (!(SPSR & (1 << SPIF))) {}
  }
  //------------------------------------------------------------------------------
  inline void SdSpiAltDriver::send(const uint8_t* buf , size_t n) {
    if (n == 0) {
      return;
    }
    SPDR = buf[0];
    if (n > 1) {
      uint8_t b = buf[1];
      size_t i = 2;
      while (1) {
        while (!(SPSR & (1 << SPIF))) {}
        SPDR = b;
        if (i == n) {
          break;
        }
        b = buf[i++];
      }
    }
    while (!(SPSR & (1 << SPIF))) {}
  }
  #endif  // __AVR__
  #endif  // SdSpiDriver_h
  