Subversion Repositories FlightCtrl

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + 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),
// + dass eine Nutzung (auch auszugsweise) nur für den privaten (nicht-kommerziellen) Gebrauch zulässig ist.
// + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt
// + bzgl. der Nutzungsbedingungen aufzunehmen.
// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,
// + Verkauf von Luftbildaufnahmen, usw.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht,
// + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts
// + auf anderen Webseiten oder sonstigen Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de"
// + eindeutig als Ursprung verlinkt werden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion
// + Benutzung auf eigene Gefahr
// + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur
// + mit unserer Zustimmung zulässig
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + 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.
// +   * The use of this project (hardware, software, binary files, sources and documentation) is only permittet
// +     for non-commercial use (directly or indirectly)
// +     Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted
// +     with our written permission
// +   * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be
// +     clearly linked as origin
// +   * porting to systems other than hardware from www.mikrokopter.de is not allowed
// +  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// +  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// +  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// +  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// +  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// +  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// +  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// +  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN// +  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// +  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// +  POSSIBILITY OF SUCH DAMAGE.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#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 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;

volatile int16_t filteredAirPressure;

/*
 * 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_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;
  }
}


#define ADCENTER (1023/2)
#define HALFRANGE 400
uint8_t stepsize = 53;

uint16_t getAbsPressure(int advalue) {
  return (uint16_t)OCR0A * (uint16_t)stepsize + 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 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;
  int16_t step = OCR0A;
 
  // 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: // air pressure
    if (sensorInputs[AD_AIRPRESSURE] < ADCENTER-HALFRANGE) {
      // value is too low, so decrease voltage on the op amp minus input, making the value higher.
      step -= ((HALFRANGE-sensorInputs[AD_AIRPRESSURE]) / stepsize + 1);
      if (step<0) step = 0;
      OCR0A = step;
      // wait = ... (calculate something here .. calculate at what time the R/C filter is to within one sample off)
    } else if (sensorInputs[AD_AIRPRESSURE] > ADCENTER+HALFRANGE) {
      // value is too high, so increase voltage on the op amp minus input, making the value lower.
      step += ((sensorInputs[AD_AIRPRESSURE] - HALFRANGE)/stepsize + 1);
      if (step>254) step = 254;
      OCR0A = step;
      // wait = ... (calculate something here .. calculate at what time the R/C filter is to within one sample off)
    } else {
      filteredAirPressure = filterAirPressure(getAbsPressure(sensorInputs[AD_AIRPRESSURE]));
    }
    break;

  case 14: // 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 15: // 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 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;
  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;
}