// MPU-6050 Accelerometer + Gyro
// -----------------------------
//
// By arduino.cc user "Krodal".
// June 2012
// Open Source / Public Domain
// Modified by Debra - http://www.geekmomprojects.com/gyroscopes-and-accelerometers-on-a-chip/
//
// Using Arduino 1.0.1
// It will not work with an older version, 
// since Wire.endTransmission() uses a parameter 
// to hold or release the I2C bus.
//
// Documentation:
// - The InvenSense documents:
//   - "MPU-6000 and MPU-6050 Product Specification",
//     PS-MPU-6000A.pdf
//   - "MPU-6000 and MPU-6050 Register Map and Descriptions",
//     RM-MPU-6000A.pdf or RS-MPU-6000A.pdf
//   - "MPU-6000/MPU-6050 9-Axis Evaluation Board User Guide"
//     AN-MPU-6000EVB.pdf
// 
// The accuracy is 16-bits.
//
// Temperature sensor from -40 to +85 degrees Celsius
//   340 per degrees, -512 at 35 degrees.
//
// At power-up, all registers are zero, except these two:
//      Register 0x6B (PWR_MGMT_2) = 0x40  (I read zero).
//      Register 0x75 (WHO_AM_I)   = 0x68.
// 

#include "MPU6050.h"      //quote marks are local
#include <USIWire.h>      //<> is global

#define output(directions,pin) (directions |= pin) // set port direction for output
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define bit_delay_time 104 // bit delay for 9600 with overhead
#define bit_delay() _delay_us(bit_delay_time) // RS232 bit delay
#define half_bit_delay() _delay_us(bit_delay_time/2) // RS232 half bit delay
#define char_delay() _delay_ms(10) // char delay

// The name of the sensor is "MPU-6050".
// For program code, I omit the '-', 
// therefor I use the name "MPU6050....".

#define serial_port PORTA
#define serial_direction DDRA
//#define serial_pins PINA
//#define serial_pin_in (1 << PA4)
#define serial_pin_out (1 << PA5)


//Spoon state definitions
  int SpoonState = 0;
  int lastSpoonState = 0;
  int SpoonStates[3];

  #define SpoonDown 1
  #define SpoonFlat 2
  #define Spoops    3


// Declaring an union for the registers and the axis values.
// The byte order does not match the byte order of 
// the compiler and AVR chip.
// The AVR chip (on the Arduino board) has the Low Byte 
// at the lower address.
// But the MPU-6050 has a different order: High Byte at
// lower address, so that has to be corrected.
// The register part "reg" is only used internally, 
// and are swapped in code.
typedef union accel_t_gyro_union
{
  struct
  {
    uint8_t x_accel_h;
    uint8_t x_accel_l;
    uint8_t y_accel_h;
    uint8_t y_accel_l;
    uint8_t z_accel_h;
    uint8_t z_accel_l;
    uint8_t t_h;
    uint8_t t_l;
    uint8_t x_gyro_h;
    uint8_t x_gyro_l;
    uint8_t y_gyro_h;
    uint8_t y_gyro_l;
    uint8_t z_gyro_h;
    uint8_t z_gyro_l;
  } reg;
  struct 
  {
    int16_t x_accel;
    int16_t y_accel;
    int16_t z_accel;
    int16_t temperature;
    int16_t x_gyro;
    int16_t y_gyro;
    int16_t z_gyro;
  } value;
};
  

int read_gyro_accel_vals(uint8_t* accel_t_gyro_ptr) {
  // Read the raw values.
  // Read 14 bytes at once, 
  // containing acceleration, temperature and gyro.
  // With the default settings of the MPU-6050,
  // there is no filter enabled, and the values
  // are not very stable.  Returns the error value
  
  accel_t_gyro_union* accel_t_gyro = (accel_t_gyro_union *) accel_t_gyro_ptr;
   
  int error = MPU6050_read (MPU6050_ACCEL_XOUT_H, (uint8_t *) accel_t_gyro, sizeof(*accel_t_gyro));

  // Swap all high and low bytes.
  // After this, the registers values are swapped, 
  // so the structure name like x_accel_l does no 
  // longer contain the lower byte.
  uint8_t swap;
  #define SWAP(x,y) swap = x; x = y; y = swap

  SWAP ((*accel_t_gyro).reg.x_accel_h, (*accel_t_gyro).reg.x_accel_l);
  SWAP ((*accel_t_gyro).reg.y_accel_h, (*accel_t_gyro).reg.y_accel_l);
  SWAP ((*accel_t_gyro).reg.z_accel_h, (*accel_t_gyro).reg.z_accel_l);
  SWAP ((*accel_t_gyro).reg.t_h, (*accel_t_gyro).reg.t_l);
  SWAP ((*accel_t_gyro).reg.x_gyro_h, (*accel_t_gyro).reg.x_gyro_l);
  SWAP ((*accel_t_gyro).reg.y_gyro_h, (*accel_t_gyro).reg.y_gyro_l);
  SWAP ((*accel_t_gyro).reg.z_gyro_h, (*accel_t_gyro).reg.z_gyro_l);
  
  return error;
}

void put_char(volatile unsigned char *port, unsigned char pin, char txchar) {
   //
   // send character in txchar on port pin
   //    assumes line driver (inverts bits)
   //
   // start bit
   //
   cli();
   clear(*port,pin);
   bit_delay();
   //
   // unrolled loop to write data bits
   //
   if bit_test(txchar,0)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,1)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,2)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,3)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,4)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,5)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,6)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,7)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   //
   // stop bit
   //
   set(*port,pin);
   bit_delay();
   sei();
   //
   // char delay
   //
   bit_delay();
   }

void put_string(volatile unsigned char *port, unsigned char pin, char *str) {
   //
   // print a null-terminated string
   //
   static int index;
   index = 0;
   do {
      put_char(port, pin, str[index]);
      ++index;
      } while (str[index] != 0);
   }
   
void setup()
{      
  int error;
  uint8_t c;
   set(serial_port, serial_pin_out);
   output(serial_direction, serial_pin_out);
   put_string(&serial_port, serial_pin_out, "started\n");


//  Serial.begin(115200);
  /*
  Serial.println(F("InvenSense MPU-6050"));
  Serial.println(F("June 2012"));
  */
  // Initialize the 'Wire' class for the I2C-bus.
  Wire.begin();


  // default at power-up:
  //    Gyro at 250 degrees second
  //    Acceleration at 2g
  //    Clock source at internal 8MHz
  //    The device is in sleep mode.
  //

  error = MPU6050_read (MPU6050_WHO_AM_I, &c, 1);
  /*
  Serial.print(F("WHO_AM_I : "));
  Serial.print(c,HEX);
  Serial.print(F(", error = "));
  Serial.println(error,DEC);
  */

  // According to the datasheet, the 'sleep' bit
  // should read a '1'. But I read a '0'.
  // That bit has to be cleared, since the sensor
  // is in sleep mode at power-up. Even if the
  // bit reads '0'.
  error = MPU6050_read (MPU6050_PWR_MGMT_2, &c, 1);
  /*
  Serial.print(F("PWR_MGMT_2 : "));
  Serial.print(c,HEX);
  Serial.print(F(", error = "));
  Serial.println(error,DEC);
  */

  // Clear the 'sleep' bit to start the sensor.
  MPU6050_write_reg (MPU6050_PWR_MGMT_1, 0);
  
  //Initialize the angles
  //calibrate_sensors();  
   //
   // initialize output pins
   //
}

void loop()
{
  int error =0;
  accel_t_gyro_union accel_t_gyro;

  /*
  Serial.println(F(""));
  Serial.println(F("MPU-6050"));
  */

int16_t x_accel=0;
int16_t y_accel=0;
int16_t z_accel=0;

for (int i = 0; i < 32; i++) {
    error += read_gyro_accel_vals((uint8_t *) &accel_t_gyro);
    x_accel += accel_t_gyro.value.x_accel;
//    y_accel += accel_t_gyro.value.y_accel;
//    z_accel += accel_t_gyro.value.z_accel;

    delay(10);
  }
 
  x_accel /= 32;
//  y_accel /= 32;
//  z_accel /= 32;
//int16_t x = x_accel;
//int16_t y = y_accel;
//int16_t z = z_accel;
 
/*
 //declaring the state of the spoon
 if (x_accel <= -15) SpoonState = SpoonDown;
 
 if ((x_accel <= 15) && (x_accel >= -15)) SpoonState = SpoonFlat;
  
 if ((x_accel >= 20) || (y_accel >= 60) || (y_accel <= -40)) SpoonState = Spoops;
  
  
 
  //if the last spoon state is not the same it will print the current state
  if (lastSpoonState != SpoonState) {
    lastSpoonState = SpoonState;
      Serial.println(SpoonState);  
    SpoonStates[2]=SpoonStates[1];
    SpoonStates[1]=SpoonStates[0];
    SpoonStates[0]=SpoonState;
    if ((SpoonStates[0]==SpoonFlat) && (SpoonStates[1]==SpoonDown) && (SpoonStates[2]==SpoonFlat));
      Serial.println("squirt");
    
  }
*/

char buff [50];
sprintf (buff, "%02X, %d, %d, %d \n",error , x_accel, y_accel, z_accel);
put_string(&serial_port, serial_pin_out, buff);
  // Delay so we don't swamp the serial port
  delay(100);
  //Serial.write(10);
}


// --------------------------------------------------------
// MPU6050_read
//
// This is a common function to read multiple bytes 
// from an I2C device.
//
// It uses the boolean parameter for Wire.endTransMission()
// to be able to hold or release the I2C-bus. 
// This is implemented in Arduino 1.0.1.
//
// Only this function is used to read. 
// There is no function for a single byte.
//
int MPU6050_read(int start, uint8_t *buffer, int size)
{
  int i, n, error;

  Wire.beginTransmission(MPU6050_I2C_ADDRESS);
  n = Wire.write(start);
  if (n != 1)
    return (-10);

  n = Wire.endTransmission(false);    // hold the I2C-bus
  if (n != 0)
    return (n);

  // Third parameter is true: relase I2C-bus after data is read.
  Wire.requestFrom(MPU6050_I2C_ADDRESS, size, true);
  i = 0;
  while(Wire.available() && i<size)
  {
    buffer[i++]=Wire.read();
  }
  if ( i != size)
    return (-11);

  return (0);  // return : no error
}


// --------------------------------------------------------
// MPU6050_write
//
// This is a common function to write multiple bytes to an I2C device.
//
// If only a single register is written,
// use the function MPU_6050_write_reg().
//
// Parameters:
//   start : Start address, use a define for the register
//   pData : A pointer to the data to write.
//   size  : The number of bytes to write.
//
// If only a single register is written, a pointer
// to the data has to be used, and the size is
// a single byte:
//   int data = 0;        // the data to write
//   MPU6050_write (MPU6050_PWR_MGMT_1, &c, 1);
//
int MPU6050_write(int start, const uint8_t *pData, int size)
{
  int n, error;

  Wire.beginTransmission(MPU6050_I2C_ADDRESS);
  n = Wire.write(start);        // write the start address
  if (n != 1)
    return (-20);

  n = Wire.write(pData, size);  // write data bytes
  if (n != size)
    return (-21);

  error = Wire.endTransmission(true); // release the I2C-bus
  if (error != 0)
    return (error);

  return (0);         // return : no error
}

// --------------------------------------------------------
// MPU6050_write_reg
//
// An extra function to write a single register.
// It is just a wrapper around the MPU_6050_write()
// function, and it is only a convenient function
// to make it easier to write a single register.
//
int MPU6050_write_reg(int reg, uint8_t data)
{
  int error;

  error = MPU6050_write(reg, &data, 1);

  return (error);
}