text: ////////////////////////////////////////////////////////////////////////////
  //
  //  This file is part of RTIMULib
  //
  //  Copyright (c) 2014, richards-tech
  //
  //  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.
  
  //  The MPU-9250 and SPI driver code is based on code generously supplied by
  //  staslock@gmail.com (www.clickdrive.io)
  
  #ifndef _RTIMUHAL_H
  #define	_RTIMUHAL_H
  
  #include <stdio.h>
  #include <math.h>
  #include <stdint.h>
  #include <fcntl.h>
  #include <string.h>
  #include <stdlib.h>
  
  #ifndef HAL_QUIET
  #define HAL_INFO(m) { printf("%s", m); fflush(stdout); }
  #define HAL_INFO1(m, x) { printf(m, x); fflush(stdout); }
  #define HAL_INFO2(m, x, y) { printf(m, x, y); fflush(stdout); }
  #define HAL_INFO3(m, x, y, z) { printf(m, x, y, z); fflush(stdout); }
  #define HAL_INFO4(m, x, y, z, a) { printf(m, x, y, z, a); fflush(stdout); }
  #define HAL_INFO5(m, x, y, z, a, b) { printf(m, x, y, z, a, b); fflush(stdout); }
  #define HAL_ERROR(m)    fprintf(stderr, m);
  #define HAL_ERROR1(m, x)    fprintf(stderr, m, x);
  #define HAL_ERROR2(m, x, y)    fprintf(stderr, m, x, y);
  #define HAL_ERROR3(m, x, y, z)    fprintf(stderr, m, x, y, z);
  #define HAL_ERROR4(m, x, y, z, a)    fprintf(stderr, m, x, y, z, a);
  
  #else
  
  #define HAL_INFO(m)
  #define HAL_INFO1(m, x)
  #define HAL_INFO2(m, x, y)
  #define HAL_INFO3(m, x, y, z)
  #define HAL_INFO4(m, x, y, z, a)
  #define HAL_INFO5(m, x, y, z, a, b)
  #define HAL_ERROR(m)
  #define HAL_ERROR1(m, x)
  #define HAL_ERROR2(m, x, y)
  #define HAL_ERROR3(m, x, y, z)
  #define HAL_ERROR4(m, x, y, z, a)
  
  #endif
  
  #ifndef WIN32
  #include <sys/ioctl.h>
  #include <linux/i2c-dev.h>
  #include <unistd.h>
  #include <sys/time.h>
  #endif
  
  #define MAX_WRITE_LEN                   255
  #define MAX_READ_LEN                    255
  
  class RTIMUHal
  {
  public:
      RTIMUHal();
      virtual ~RTIMUHal();
  
      bool m_busIsI2C;                                        // true if I2C bus in use, false if SPI in use
      unsigned char m_I2CBus;                                 // I2C bus of the imu (eg 1 for Raspberry Pi usually)
      unsigned char m_SPIBus;                                 // SPI bus of the imu (eg 0 for Raspberry Pi usually)
      unsigned int m_SPISpeed;                                // speed of interface
  
      bool HALOpen();
      bool HALRead(unsigned char slaveAddr, unsigned char regAddr, unsigned char length,
                   unsigned char *data, const char *errorMsg);
      bool HALWrite(unsigned char slaveAddr, unsigned char regAddr,
                    unsigned char length, unsigned char const *data, const char *errorMsg);
      bool HALWrite(unsigned char slaveAddr, unsigned char regAddr,
                    unsigned char const data, const char *errorMsg);
  
      void delayMs(int milliSeconds);
  
  protected:
      void I2CClose();
      bool I2CSelectSlave(unsigned char slaveAddr, const char *errorMsg);
      void SPIClose();
      bool ifWrite(unsigned char *data, unsigned char length);
  
  private:
      int m_I2C;
      unsigned char m_currentSlave;
      int m_SPI;
  };
  
  #endif // _RTIMUHAL_H
  