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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
// + Nur für den privaten Gebrauch
// + www.MikroKopter.com
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation),
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// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// + Benutzung auf eigene Gefahr
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Redistributions of source code (with or without modifications) must retain the above copyright notice,
// + this list of conditions and the following disclaimer.
// +   * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived
// +     from this software without specific prior written permission.
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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "analog.h"

#include "sensors.h"

// for Delay functions
#include "timer0.h"

// For DebugOut
#include "uart0.h"

// For reading and writing acc. meter offsets.
#include "eeprom.h"

/*
 * For each A/D conversion cycle, each analog channel is sampled a number of times
 * (see array channelsForStates), and the results for each channel are summed.
 * Here are those for the gyros and the acc. meters. They are not zero-offset.
 * They are exported in the analog.h file - but please do not use them! The only
 * reason for the export is that the ENC-03_FC1.3 modules needs them for calibrating
 * the offsets with the DAC.
 */

volatile int16_t rawGyroSum[3];
volatile int16_t acc[3];
volatile int16_t filteredAcc[2]={0,0};

/*
 * These 4 exported variables are zero-offset. The "PID" ones are used
 * in the attitude control as rotation rates. The "ATT" ones are for
 * integration to angles.
 */

volatile int16_t gyro_PID[2];
volatile int16_t gyro_ATT[2];
volatile int16_t gyroD[2];
volatile int16_t yawGyro;

/*
 * Offset values. These are the raw gyro and acc. meter sums when the copter is
 * standing still. They are used for adjusting the gyro and acc. meter values
 * to be centered on zero.
 */

volatile int16_t gyroOffset[3] = {
        512 * GYRO_SUMMATION_FACTOR_PITCHROLL,
        512 * GYRO_SUMMATION_FACTOR_PITCHROLL,
        512 * GYRO_SUMMATION_FACTOR_YAW
};

volatile int16_t accOffset[3] = {
        512 * ACC_SUMMATION_FACTOR_PITCHROLL,
        512 * ACC_SUMMATION_FACTOR_PITCHROLL,
        512 * ACC_SUMMATION_FACTOR_Z
};

/*
 * This allows some experimentation with the gyro filters.
 * Should be replaced by #define's later on...
 */

volatile uint8_t GYROS_PID_FILTER;
volatile uint8_t GYROS_ATT_FILTER;
volatile uint8_t GYROS_D_FILTER;
volatile uint8_t ACC_FILTER;

/*
 * Air pressure measurement.
 */

#define MIN_RAWPRESSURE 200
#define MAX_RAWPRESSURE (1023-MIN_RAWPRESSURE)
volatile uint8_t rangewidth = 53;
volatile uint16_t rawAirPressure;
volatile uint16_t filteredAirPressure;

/*
 * Battery voltage, in units of: 1k/11k / 3V * 1024 = 31.03 per volt.
 * That is divided by 3 below, for a final 10.34 per volt.
 * So the initial value of 100 is for 9.7 volts.
 */

volatile int16_t UBat = 100;

/*
 * Control and status.
 */

volatile uint16_t ADCycleCount = 0;
volatile uint8_t analogDataReady = 1;

/*
 * Experiment: Measuring vibration-induced sensor noise.
 */

volatile uint16_t gyroNoisePeak[2];
volatile uint16_t accNoisePeak[2];

// ADC channels
#define AD_GYRO_YAW       0
#define AD_GYRO_ROLL      1
#define AD_GYRO_PITCH     2
#define AD_AIRPRESSURE    3
#define AD_UBAT           4
#define AD_ACC_Z          5
#define AD_ACC_ROLL       6
#define AD_ACC_PITCH      7

/*
 * Table of AD converter inputs for each state.
 * The number of samples summed for each channel is equal to
 * the number of times the channel appears in the array.
 * The max. number of samples that can be taken in 2 ms is:
 * 20e6 / 128 / 13 / (1/2e-3) = 24. Since the main control
 * loop needs a little time between reading AD values and
 * re-enabling ADC, the real limit is (how much?) lower.
 * The acc. sensor is sampled even if not used - or installed
 * at all. The cost is not significant.
 */


const uint8_t channelsForStates[] PROGMEM = {
  AD_GYRO_PITCH,
  AD_GYRO_ROLL,
  AD_GYRO_YAW,

  AD_ACC_PITCH,
  AD_ACC_ROLL,
  // AD_AIRPRESSURE,
 
  AD_GYRO_PITCH,
  AD_GYRO_ROLL,
  AD_ACC_Z,       // at 7, measure Z acc.

  AD_GYRO_PITCH,
  AD_GYRO_ROLL,
  AD_GYRO_YAW,    // at 10, finish yaw gyro

  AD_ACC_PITCH,   // at 11, finish pitch axis acc.
  AD_ACC_ROLL,    // at 12, finish roll axis acc.
  AD_AIRPRESSURE, // at 13, finish air pressure.

  AD_GYRO_PITCH,  // at 14, finish pitch gyro
  AD_GYRO_ROLL,   // at 15, finish roll gyro
  AD_UBAT         // at 16, measure battery.
};

// Feature removed. Could be reintroduced later - but should work for all gyro types then.
// uint8_t GyroDefectPitch = 0, GyroDefectRoll = 0, GyroDefectYaw = 0;

void analog_init(void) {
  uint8_t sreg = SREG;
  // disable all interrupts before reconfiguration
  cli();

  //ADC0 ... ADC7 is connected to PortA pin 0 ... 7
  DDRA = 0x00;
  PORTA = 0x00;
  // Digital Input Disable Register 0
  // Disable digital input buffer for analog adc_channel pins
  DIDR0 = 0xFF;
  // external reference, adjust data to the right
  ADMUX &= ~((1 << REFS1)|(1 << REFS0)|(1 << ADLAR));
  // set muxer to ADC adc_channel 0 (0 to 7 is a valid choice)
  ADMUX = (ADMUX & 0xE0) | AD_GYRO_PITCH;
  //Set ADC Control and Status Register A
  //Auto Trigger Enable, Prescaler Select Bits to Division Factor 128, i.e. ADC clock = SYSCKL/128 = 156.25 kHz
  ADCSRA = (0<<ADEN)|(0<<ADSC)|(0<<ADATE)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0)|(0<<ADIE);
  //Set ADC Control and Status Register B
  //Trigger Source to Free Running Mode
  ADCSRB &= ~((1 << ADTS2)|(1 << ADTS1)|(1 << ADTS0));
  // Start AD conversion
  analog_start();
  // restore global interrupt flags
  SREG = sreg;
}

void measureNoise(const int16_t sensor, volatile uint16_t* const noiseMeasurement, const uint8_t damping) {
  if (sensor > (int16_t)(*noiseMeasurement)) {
    *noiseMeasurement = sensor;
  } else if (-sensor > (int16_t)(*noiseMeasurement)) {
    *noiseMeasurement = -sensor;
  } else if (*noiseMeasurement > damping) {
    *noiseMeasurement -= damping;
  } else {
    *noiseMeasurement = 0;
  }
}

uint16_t getAbsPressure(int advalue) {
  return (uint16_t)OCR0A * (uint16_t)rangewidth + advalue;
}

uint16_t filterAirPressure(uint16_t rawpressure) {
  return rawpressure;
}

/*****************************************************
 * Interrupt Service Routine for ADC            
 * Runs at 312.5 kHz or 3.2 µs. When all states are
 * processed the interrupt is disabled and further
 * AD conversions are stopped.
 *****************************************************/

ISR(ADC_vect) {
  static uint8_t ad_channel = AD_GYRO_PITCH, state = 0;
  static uint16_t sensorInputs[8] = {0,0,0,0,0,0,0,0};
  static uint8_t pressure_wait = 10;
  uint8_t i, axis;
  int16_t range;
 
  // for various filters...
  int16_t tempOffsetGyro, tempGyro;
 
  sensorInputs[ad_channel] += ADC;

  /*
   * Actually we don't need this "switch". We could do all the sampling into the
   * sensorInputs array first, and all the processing after the last sample.
   */

  switch(state++) {
  case 7: // Z acc     
  if (ACC_REVERSED[Z])
    acc[Z] = accOffset[Z] - sensorInputs[AD_ACC_Z];
  else
    acc[Z] = sensorInputs[AD_ACC_Z] - accOffset[Z];
  break;
   
  case 10: // yaw gyro
    rawGyroSum[YAW] = sensorInputs[AD_GYRO_YAW];
    if (GYRO_REVERSED[YAW])
      yawGyro = gyroOffset[YAW] - sensorInputs[AD_GYRO_YAW];
    else
      yawGyro = sensorInputs[AD_GYRO_YAW] - gyroOffset[YAW];
    break;
   
  case 11: // pitch axis acc.
    if (ACC_REVERSED[PITCH])
      acc[PITCH] = accOffset[PITCH] - sensorInputs[AD_ACC_PITCH];
    else
      acc[PITCH] = sensorInputs[AD_ACC_PITCH] - accOffset[PITCH];

    filteredAcc[PITCH] = (filteredAcc[PITCH] * (ACC_FILTER-1) + acc[PITCH]) / ACC_FILTER;
    measureNoise(acc[PITCH], &accNoisePeak[PITCH], 1);
    break;
   
  case 12: // roll axis acc.
    if (ACC_REVERSED[ROLL])
      acc[ROLL] = accOffset[ROLL] - sensorInputs[AD_ACC_ROLL];
    else
      acc[ROLL] = sensorInputs[AD_ACC_ROLL] - accOffset[ROLL];
    filteredAcc[ROLL] = (filteredAcc[ROLL] * (ACC_FILTER-1) + acc[ROLL]) / ACC_FILTER;
    measureNoise(acc[ROLL], &accNoisePeak[ROLL], 1);
    break;

  case 13: // air pressure
    if (pressure_wait) {
      // A range switch was done recently. Wait for steadying.
      pressure_wait--;
      break;
    }
    range = OCR0A;
    rawAirPressure = sensorInputs[AD_AIRPRESSURE];
    if (rawAirPressure < MIN_RAWPRESSURE) {
      // value is too low, so decrease voltage on the op amp minus input, making the value higher.
      range -= (MAX_RAWPRESSURE - rawAirPressure) / rangewidth - 1;
      if (range < 0) range = 0;
      pressure_wait = (OCR0A - range) * 4;
      OCR0A = range;
    } else if (rawAirPressure > MAX_RAWPRESSURE) {
      // value is too high, so increase voltage on the op amp minus input, making the value lower.
      range += (rawAirPressure - MIN_RAWPRESSURE) / rangewidth - 1;
      if (range > 254) range = 254;
      pressure_wait = (range - OCR0A) * 4;
      OCR0A = range;
    } else {
      filteredAirPressure = filterAirPressure(getAbsPressure(rawAirPressure));
    }
   
    DebugOut.Analog[13] = range;
    DebugOut.Analog[14] = rawAirPressure;
    DebugOut.Analog[15] = filteredAirPressure;
    break;

  case 14:
  case 15: // pitch or roll gyro.
    axis = state - 15;
    tempGyro = rawGyroSum[axis] = sensorInputs[AD_GYRO_PITCH - axis];
        // DebugOut.Analog[6 + 3 * axis ] = tempGyro;
    /*
     * Process the gyro data for the PID controller.
     */

    // 1) Extrapolate: Near the ends of the range, we boost the input significantly. This simulates a
    //    gyro with a wider range, and helps counter saturation at full control.

    if (staticParams.GlobalConfig & CFG_ROTARY_RATE_LIMITER) {
      if (tempGyro < SENSOR_MIN_PITCHROLL) {
        tempGyro = tempGyro * EXTRAPOLATION_SLOPE - EXTRAPOLATION_LIMIT;
      }
      else if (tempGyro > SENSOR_MAX_PITCHROLL) {
        tempGyro = (tempGyro - SENSOR_MAX_PITCHROLL) * EXTRAPOLATION_SLOPE + SENSOR_MAX_PITCHROLL;
      }
    }

    // 2) Apply sign and offset, scale before filtering.
    if (GYRO_REVERSED[axis]) {
      tempOffsetGyro = (gyroOffset[axis] - tempGyro) * GYRO_FACTOR_PITCHROLL;
    } else {
      tempOffsetGyro = (tempGyro - gyroOffset[axis]) * GYRO_FACTOR_PITCHROLL;
    }

    // 3) Scale and filter.
    tempOffsetGyro = (gyro_PID[axis] * (GYROS_PID_FILTER-1) + tempOffsetGyro) / GYROS_PID_FILTER;

    // 4) Measure noise.
    measureNoise(tempOffsetGyro, &gyroNoisePeak[axis], GYRO_NOISE_MEASUREMENT_DAMPING);

    // 5) Differential measurement.
    gyroD[axis] = (gyroD[axis] * (GYROS_D_FILTER-1) + (tempOffsetGyro - gyro_PID[axis])) / GYROS_D_FILTER;

    // 6) Done.
    gyro_PID[axis] = tempOffsetGyro;

    /*
     * Now process the data for attitude angles.
     */

    tempGyro = rawGyroSum[axis];
   
    // 1) Apply sign and offset, scale before filtering.
    if (GYRO_REVERSED[axis]) {
      tempOffsetGyro = (gyroOffset[axis] - tempGyro) * GYRO_FACTOR_PITCHROLL;
    } else {
      tempOffsetGyro = (tempGyro - gyroOffset[axis]) * GYRO_FACTOR_PITCHROLL;
    }
   
    // 2) Filter.
    gyro_ATT[axis] = (gyro_ATT[axis] * (GYROS_ATT_FILTER-1) + tempOffsetGyro) / GYROS_ATT_FILTER;
    break;
   
  case 16:
    // battery
    UBat = (3 * UBat + sensorInputs[AD_UBAT] / 3) / 4;
    analogDataReady = 1; // mark
    ADCycleCount++;
    // Stop the sampling. Cycle is over.
    state = 0;
    for (i=0; i<8; i++) {
      sensorInputs[i] = 0;
    }
    break;
  default: {} // do nothing.
  }

  // set up for next state.
  ad_channel = pgm_read_byte(&channelsForStates[state]);
  // ad_channel = channelsForStates[state];
     
  // set adc muxer to next ad_channel
  ADMUX = (ADMUX & 0xE0) | ad_channel;
  // after full cycle stop further interrupts
  if(state) analog_start();
}

void analog_calibrate(void) {
#define GYRO_OFFSET_CYCLES 32
  uint8_t i, axis;
  int32_t deltaOffsets[3] = {0,0,0};
  int16_t filteredDelta;

  // Set the filters... to be removed again, once some good settings are found.
  GYROS_PID_FILTER = (dynamicParams.UserParams[4]   & 0b00000011)       + 1;
  GYROS_ATT_FILTER = ((dynamicParams.UserParams[4]  & 0b00001100) >> 2) + 1;
  GYROS_D_FILTER = ((dynamicParams.UserParams[4]    & 0b00110000) >> 4) + 1;
  ACC_FILTER = ((dynamicParams.UserParams[4]        & 0b11000000) >> 6) + 1;

  gyro_calibrate();

  // determine gyro bias by averaging (requires that the copter does not rotate around any axis!)
  for(i=0; i < GYRO_OFFSET_CYCLES; i++) {
    Delay_ms_Mess(10);
    for (axis=0; axis<=YAW; axis++) {
      deltaOffsets[axis] += rawGyroSum[axis] - gyroOffset[axis];
    }
  }

  for (axis=0; axis<=YAW; axis++) {
    filteredDelta = (deltaOffsets[axis] + GYRO_OFFSET_CYCLES / 2) / GYRO_OFFSET_CYCLES;
    gyroOffset[axis] += filteredDelta;
  }

  // Noise is relative to offset. So, reset noise measurements when changing offsets.
  gyroNoisePeak[PITCH] = gyroNoisePeak[ROLL] = 0;

  accOffset[PITCH] = GetParamWord(PID_ACC_PITCH);
  accOffset[ROLL]  = GetParamWord(PID_ACC_ROLL);
  accOffset[Z]     = GetParamWord(PID_ACC_Z);

  Delay_ms_Mess(100);
}

/*
 * Find acc. offsets for a neutral reading, and write them to EEPROM.
 * Does not (!} update the local variables. This must be done with a
 * call to analog_calibrate() - this always (?) is done by the caller
 * anyway. There would be nothing wrong with updating the variables
 * directly from here, though.
 */

void analog_calibrateAcc(void) {
#define ACC_OFFSET_CYCLES 10
  uint8_t i, axis;
  int32_t deltaOffset[3] = {0,0,0};
  int16_t filteredDelta;
  // int16_t pressureDiff, savedRawAirPressure;

  for(i=0; i < ACC_OFFSET_CYCLES; i++) {
    Delay_ms_Mess(10);
    for (axis=0; axis<=YAW; axis++) {
          deltaOffset[axis] += acc[axis];
        }
  }

  for (axis=0; axis<=YAW; axis++) {
    filteredDelta = (deltaOffset[axis] + ACC_OFFSET_CYCLES / 2) / ACC_OFFSET_CYCLES;
    accOffset[axis] += ACC_REVERSED[axis] ? -filteredDelta : filteredDelta;
  }

  // Save ACC neutral settings to eeprom
  SetParamWord(PID_ACC_PITCH, accOffset[PITCH]);
  SetParamWord(PID_ACC_ROLL,  accOffset[ROLL]);
  SetParamWord(PID_ACC_Z,     accOffset[Z]);

  // Noise is relative to offset. So, reset noise measurements when
  // changing offsets.
  accNoisePeak[PITCH] = accNoisePeak[ROLL] = 0;
 
  // Setting offset values has an influence in the analog.c ISR
  // Therefore run measurement for 100ms to achive stable readings
  Delay_ms_Mess(100);
 
  // Set the feedback so that air pressure ends up in the middle of the range.
  // (raw pressure high --> OCR0A also high...)
  // OCR0A += (rawAirPressure - 512) / rangewidth;
  // Delay_ms_Mess(500);

  /*
    pressureDiff = 0;
    DebugOut.Analog[16] = rawAirPressure;

    #define PRESSURE_CAL_CYCLE_COUNT 2
    for (i=0; i<PRESSURE_CAL_CYCLE_COUNT; i++) {
    savedRawAirPressure = rawAirPressure;
    OCR0A++;
    Delay_ms_Mess(200);
    // raw pressure will decrease.
    pressureDiff += (savedRawAirPressure - rawAirPressure);

    savedRawAirPressure = rawAirPressure;
    OCR0A--;
    Delay_ms_Mess(200);
    // raw pressure will increase.
    pressureDiff += (rawAirPressure - savedRawAirPressure);
    }

    DebugOut.Analog[16] = rangewidth =
    (pressureDiff + PRESSURE_CAL_CYCLE_COUNT * 2 - 1) / (PRESSURE_CAL_CYCLE_COUNT * 2);
  */

}