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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"

/*

 * Arrays could have been used arrays for the 2 * 3 axes, but despite some repetition,

 * the code is easier to read without.

 *

 * For each A/D conversion cycle, each channel (eg. the yaw gyro, or the Z axis

 * accelerometer) 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 rawPitchGyroSum, rawRollGyroSum, rawYawGyroSum;

volatile int16_t pitchAxisAcc = 0, rollAxisAcc = 0, ZAxisAcc = 0;

volatile int16_t filteredPitchAxisAcc = 0, filteredRollAxisAcc = 0;

// that float one - "Top" - is missing.

/*

 * These 4 exported variables are zero-offset. The "filtered" ones are

 * (if configured to with the GYROS_SECONDORDERFILTER define) low pass

 * filtered versions of the other 2.

 * They are derived from the "raw" values above, by zero-offsetting.

 */

volatile int16_t hiResPitchGyro = 0, hiResRollGyro = 0;

volatile int16_t filteredHiResPitchGyro = 0, filteredHiResRollGyro = 0;

volatile int16_t pitchGyroD = 0, rollGyroD = 0;

volatile int16_t yawGyro = 0;

/*

 * 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 zero when the copter stands still.

 */

volatile int16_t pitchOffset, rollOffset, yawOffset;

volatile int16_t pitchAxisAccOffset, rollAxisAccOffset, ZAxisAccOffset;

/*

 * This allows some experimentation with the gyro filters.

 * Should be replaced by #define's later on...

 */

volatile uint8_t GYROS_FIRSTORDERFILTER;

volatile uint8_t GYROS_SECONDORDERFILTER;

volatile uint8_t GYROS_DFILTER;

volatile uint8_t ACC_FILTER;

// Air pressure (no support right now).

// volatile int32_t AirPressure = 32000;

// volatile uint8_t average_pressure = 0;

// volatile int16_t StartAirPressure;

// volatile uint16_t ReadingAirPressure = 1023;

// volatile int16_t HeightD = 0;

/*

 * 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 pitchGyroNoisePeak, rollGyroNoisePeak;

volatile uint16_t pitchAccNoisePeak, rollAccNoisePeak;

// 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_ROLL,

  AD_ACC_PITCH,

  AD_GYRO_PITCH,

  AD_GYRO_ROLL,

  AD_ACC_Z,       // at 7, finish 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_GYRO_PITCH,  // at 13, finish pitch gyro

  AD_GYRO_ROLL,   // at 14, finish roll gyro

  AD_UBAT         // at 15, 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;

  }

}

/*****************************************************/

/*     Interrupt Service Routine for ADC             */

/*****************************************************/

// Runs at 312.5 kHz or 3.2 µs

// When all states are processed the interrupt is disabled

// and the update of further AD conversions is 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};

  uint8_t i;

  // for various filters...

  static int16_t pitchGyroFilter, rollGyroFilter, tempOffsetGyro;

  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      

#ifdef ACC_REVERSE_ZAXIS

    ZAxisAcc = -ZAxisAccOffset - sensorInputs[AD_ACC_Z];

#else

    ZAxisAcc = sensorInputs[AD_ACC_Z] - ZAxisAccOffset;

#endif

    break;

  case 10: // yaw gyro

    rawYawGyroSum = sensorInputs[AD_GYRO_YAW];

#ifdef GYRO_REVERSE_YAW

    yawGyro = rawYawGyroSum - yawOffset;

#else

    yawGyro = yawOffset - rawYawGyroSum; // negative is "default" (FC 1.0-1.3).

#endif

    break;

  case 11: // pitch axis acc.

#ifdef ACC_REVERSE_PITCHAXIS

    pitchAxisAcc = -pitchAxisAccOffset - sensorInputs[AD_ACC_PITCH];

#else

    pitchAxisAcc = sensorInputs[AD_ACC_PITCH] - pitchAxisAccOffset;

#endif

    filteredPitchAxisAcc = (filteredPitchAxisAcc * (ACC_FILTER-1) + pitchAxisAcc) / ACC_FILTER;

    measureNoise(pitchAxisAcc, &pitchAccNoisePeak, 1);

    break;

  case 12: // roll axis acc.

#ifdef ACC_REVERSE_ROLLAXIS

    rollAxisAcc = sensorInputs[AD_ACC_ROLL] - rollAxisAccOffset;

#else

    rollAxisAcc = -rollAxisAccOffset - sensorInputs[AD_ACC_ROLL];

#endif

    filteredRollAxisAcc = (filteredRollAxisAcc * (ACC_FILTER-1) + rollAxisAcc) / ACC_FILTER;

    measureNoise(rollAxisAcc, &rollAccNoisePeak, 1);

    break;

  case 13: // pitch gyro

    rawPitchGyroSum = sensorInputs[AD_GYRO_PITCH];

    // Filter already before offsetting. The offsetting resolution improvement obtained by divding by

    // GYROS_FIRSTORDERFILTER _after_ offsetting is too small to be worth pursuing.

    pitchGyroFilter = (pitchGyroFilter * (GYROS_FIRSTORDERFILTER-1) + rawPitchGyroSum * GYRO_FACTOR_PITCHROLL) / GYROS_FIRSTORDERFILTER;

    // Offset to 0.

#ifdef GYROS_REVERSE_PITCH

    tempOffsetGyro = pitchOffset - pitchGyroFilter;

#else

    tempOffsetGyro = pitchGyroFilter - pitchOffset;

#endif

    // Calculate the delta from last shot and filter it.

    pitchGyroD = (pitchGyroD * (GYROS_DFILTER-1) + (tempOffsetGyro - hiResPitchGyro)) / GYROS_DFILTER;

    // How we can overwrite the last value. This value is used for the D part of the PID controller.

    hiResPitchGyro = tempOffsetGyro;

    // Filter a little more. This value is used in integration to angles.

    filteredHiResPitchGyro = (filteredHiResPitchGyro * (GYROS_SECONDORDERFILTER-1) + hiResPitchGyro) / GYROS_SECONDORDERFILTER;

    measureNoise(hiResPitchGyro, &pitchGyroNoisePeak, GYRO_NOISE_MEASUREMENT_DAMPING);

    break;

  case 14: // Roll gyro. Works the same as pitch.

    rawRollGyroSum = sensorInputs[AD_GYRO_ROLL];

    rollGyroFilter = (rollGyroFilter * (GYROS_FIRSTORDERFILTER-1) + rawRollGyroSum * GYRO_FACTOR_PITCHROLL) / GYROS_FIRSTORDERFILTER;

#ifdef GYRO_REVERSE_ROLL

    tempOffsetGyro = rollOffset - rollGyroFilter;

#else

    tempOffsetGyro = rollGyroFilter - rollOffset;

#endif

    rollGyroD = (rollGyroD * (GYROS_DFILTER-1) + (tempOffsetGyro - hiResRollGyro)) / GYROS_DFILTER;

    hiResRollGyro = tempOffsetGyro;

    filteredHiResRollGyro = (filteredHiResRollGyro * (GYROS_SECONDORDERFILTER-1) + hiResRollGyro) / GYROS_SECONDORDERFILTER;

    measureNoise(hiResRollGyro, &rollGyroNoisePeak, GYRO_NOISE_MEASUREMENT_DAMPING);

    break;

  case 15:

    // 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;

  int32_t _pitchOffset = 0, _rollOffset = 0, _yawOffset = 0;

  // Set the filters... to be removed again, once some good settings are found.

  GYROS_FIRSTORDERFILTER = (dynamicParams.UserParams[4]   & 0b00000011)       + 1;

  GYROS_SECONDORDERFILTER = ((dynamicParams.UserParams[4] & 0b00001100) >> 2) + 1;

  GYROS_DFILTER = ((dynamicParams.UserParams[4]           & 0b00110000) >> 4) + 1;

  ACC_FILTER = ((dynamicParams.UserParams[4]              & 0b11000000) >> 6) + 1;

  pitchOffset = rollOffset = yawOffset = 0;

  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);

    _pitchOffset += rawPitchGyroSum * GYRO_FACTOR_PITCHROLL;

    _rollOffset  += rawRollGyroSum * GYRO_FACTOR_PITCHROLL;

    _yawOffset   += rawYawGyroSum;

  }

  pitchOffset = (_pitchOffset + GYRO_OFFSET_CYCLES / 2) / GYRO_OFFSET_CYCLES;

  rollOffset  = (_rollOffset  + GYRO_OFFSET_CYCLES / 2) / GYRO_OFFSET_CYCLES;

  yawOffset   = (_yawOffset   + GYRO_OFFSET_CYCLES / 2) / GYRO_OFFSET_CYCLES;

  filteredHiResPitchGyro = filteredHiResRollGyro = 0;

  pitchAxisAccOffset = (int16_t)GetParamWord(PID_ACC_NICK);

  rollAxisAccOffset  = (int16_t)GetParamWord(PID_ACC_ROLL);

  ZAxisAccOffset     = (int16_t)GetParamWord(PID_ACC_TOP);

  // Noise is relative to offset. So, reset noise measurements when

  // changing offsets.

  pitchGyroNoisePeak = rollGyroNoisePeak = 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);

}

/*

 * 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;

  int32_t _pitchAxisOffset = 0, _rollAxisOffset = 0, _ZAxisOffset = 0;

  pitchAxisAccOffset = rollAxisAccOffset = ZAxisAccOffset = 0;

  for(i=0; i < ACC_OFFSET_CYCLES; i++) {

    Delay_ms_Mess(10);

    _pitchAxisOffset += pitchAxisAcc;

    _rollAxisOffset += rollAxisAcc;

    _ZAxisOffset += ZAxisAcc;

  }

  // Save ACC neutral settings to eeprom

  SetParamWord(PID_ACC_NICK, (uint16_t)((_pitchAxisOffset + ACC_OFFSET_CYCLES / 2) / ACC_OFFSET_CYCLES));

  SetParamWord(PID_ACC_ROLL, (uint16_t)((_rollAxisOffset  + ACC_OFFSET_CYCLES / 2) / ACC_OFFSET_CYCLES));

  SetParamWord(PID_ACC_TOP,  (uint16_t)((_ZAxisOffset     + ACC_OFFSET_CYCLES / 2) / ACC_OFFSET_CYCLES));

  // Noise is relative to offset. So, reset noise measurements when

  // changing offsets.

  pitchAccNoisePeak = rollAccNoisePeak = 0;

}