Subversion Repositories FlightCtrl

#include <avr/io.h>

#include <avr/interrupt.h>

#include <avr/pgmspace.h>

#include <stdlib.h>

#include "analog.h"

#include "configuration.h"

#include "attitude.h"

#include "printf_P.h"

#include "isqrt.h"

#include "twimaster.h"

// for Delay functions

#include "timer0.h"

// For reading and writing acc. meter offsets.

#include "eeprom.h"

// For debugOut

#include "output.h"

// set ADC enable & ADC Start Conversion & ADC Interrupt Enable bit

#define startADC() (ADCSRA |= (1<<ADEN)|(1<<ADSC)|(1<<ADIE))

const char* recal = ", recalibration needed.";

volatile uint16_t ADSensorInputs[8];

/*

 * 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.

 */

int16_t gyro_PID[3];

int16_t gyro_ATT[3];

int16_t gyroD[3];

int16_t gyroDWindow[3][GYRO_D_WINDOW_LENGTH];

uint8_t gyroDWindowIdx = 0;

/*

 * Airspeed

 */

//int16_t airpressure;

//uint16_t airspeedVelocity = 0;

//int16_t airpressureWindow[AIRPRESSURE_WINDOW_LENGTH];

//uint8_t airpressureWindowIdx = 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 centered on zero.

 */

sensorOffset_t gyroOffset;

uint16_t airpressureOffset;

/*

 * In the MK coordinate system, nose-down is positive and left-roll is positive.

 * If a sensor is used in an orientation where one but not both of the axes has

 * an opposite sign, PR_ORIENTATION_REVERSED is set to 1 (true).

 * Transform:

 * pitch <- pp*pitch + pr*roll

 * roll  <- rp*pitch + rr*roll

 * Not reversed, GYRO_QUADRANT:

 * 0: pp=1, pr=0, rp=0, rr=1  // 0    degrees

 * 1: pp=1, pr=-1,rp=1, rr=1  // +45  degrees

 * 2: pp=0, pr=-1,rp=1, rr=0  // +90  degrees

 * 3: pp=-1,pr=-1,rp=1, rr=1  // +135 degrees

 * 4: pp=-1,pr=0, rp=0, rr=-1 // +180 degrees

 * 5: pp=-1,pr=1, rp=-1,rr=-1 // +225 degrees

 * 6: pp=0, pr=1, rp=-1,rr=0  // +270 degrees

 * 7: pp=1, pr=1, rp=-1,rr=1  // +315 degrees

 * Reversed, GYRO_QUADRANT:

 * 0: pp=-1,pr=0, rp=0, rr=1  // 0    degrees with pitch reversed

 * 1: pp=-1,pr=-1,rp=-1,rr=1  // +45  degrees with pitch reversed

 * 2: pp=0, pr=-1,rp=-1,rr=0  // +90  degrees with pitch reversed

 * 3: pp=1, pr=-1,rp=-1,rr=1  // +135 degrees with pitch reversed

 * 4: pp=1, pr=0, rp=0, rr=-1 // +180 degrees with pitch reversed

 * 5: pp=1, pr=1, rp=1, rr=-1 // +225 degrees with pitch reversed

 * 6: pp=0, pr=1, rp=1, rr=0  // +270 degrees with pitch reversed

 * 7: pp=-1,pr=1, rp=1, rr=1  // +315 degrees with pitch reversed

 */

void rotate(int16_t* result, uint8_t quadrant, uint8_t reversePR, uint8_t reverseYaw) {

  static const int8_t rotationTab[] = {1,1,0,-1,-1,-1,0,1};

  // Pitch to Pitch part

  int8_t xx = reversePR ? rotationTab[(quadrant+4)%8] : rotationTab[quadrant];

  // Roll to Pitch part

  int8_t xy = rotationTab[(quadrant+2)%8];

  // Pitch to Roll part

  int8_t yx = reversePR ? rotationTab[(quadrant+2)%8] : rotationTab[(quadrant+6)%8];

  // Roll to Roll part

  int8_t yy = rotationTab[quadrant];

  int16_t xIn = result[0];

  result[0] = xx*xIn + xy*result[1];

  result[1] = yx*xIn + yy*result[1];

  if (quadrant & 1) {

        // A rotation was used above, where the factors were too large by sqrt(2).

        // So, we multiply by 2^n/sqt(2) and right shift n bits, as to divide by sqrt(2).

        // A suitable value for n: Sample is 11 bits. After transformation it is the sum

        // of 2 11 bit numbers, so 12 bits. We have 4 bits left...

        result[0] = (result[0]*11) >> 4;

        result[1] = (result[1]*11) >> 4;

  }

  if (reverseYaw)

    result[3] =-result[3];

}

/*

 * 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.

 */

uint16_t UBat = 100;

/*

 * Control and status.

 */

volatile uint8_t sensorDataReady = ALL_DATA_READY;

/*

 * Experiment: Measuring vibration-induced sensor noise.

 */

uint16_t gyroNoisePeak[3];

volatile uint8_t adState;

volatile uint8_t adChannel;

// ADC channels

#define AD_UBAT           6

//#define AD_AIRPRESSURE    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_AIRPRESSURE,

  AD_UBAT

  //AD_AIRPRESSURE,

  //AD_AIRPRESSURE,

  //AD_AIRPRESSURE,

};

// 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);

        //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 = (1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);

        //Set ADC Control and Status Register B

        //Trigger Source to Free Running Mode

        ADCSRB &= ~((1<<ADTS2)|(1<<ADTS1)|(1<<ADTS0));

        startAnalogConversionCycle();

        twimaster_init();

        // restore global interrupt flags

        SREG = sreg;

}

/*

 * Here the axes of the sensor can be shuffled around.

 */

int16_t rawGyroValue(uint8_t axis) {

  return ITG3200SensorInputs[axis+1]; // skip temperature mesaurement in any case..

}

/*

uint16_t rawAccValue(uint8_t axis) {

        return sensorInputs[AD_ACC_PITCH-axis];

}

*/

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;

        }

}

void startAnalogConversionCycle(void) {

  twimaster_startCycle();

  // Stop the sampling. Cycle is over.

  for (uint8_t i = 0; i<8; i++) {

    ADSensorInputs[i] = 0;

  }

  adState = 0;

  adChannel = AD_UBAT;

  ADMUX = (ADMUX & 0xE0) | adChannel;

  startADC();

  sensorDataReady = 0;

}

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

 * Interrupt Service Routine for ADC

 * Runs at 312.5 kHz or 3.2 �s. When all states are

 * processed further conversions are stopped.

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

ISR(ADC_vect) {

  ADSensorInputs[adChannel] += ADC;

  // set up for next state.

  adState++;

  if (adState < sizeof(channelsForStates)) {

    adChannel = pgm_read_byte(&channelsForStates[adState]);

    // set adc muxer to next adChannel

    ADMUX = (ADMUX & 0xE0) | adChannel;

    // after full cycle stop further interrupts

    startADC();

  } else {

    sensorDataReady |= ADC_DATA_READY;

    // do not restart ADC converter. 

  }

}

void analog_updateGyros(void) {

  // for various filters...

  int16_t tempOffsetGyro[3], tempGyro;

  for (uint8_t axis=0; axis<3; axis++) {

    tempGyro = rawGyroValue(axis);

    /*

     * Process the gyro data for the PID controller.

     */

    // Saturation prevention was removed. No airplane rotates more than 2000 deg/s.

    // 2) Apply sign and offset, scale before filtering.

    tempOffsetGyro[axis] = (tempGyro - gyroOffset.offsets[axis]);

  }

  // 2.1: Transform axes.

  rotate(tempOffsetGyro, IMUConfig.gyroQuadrant, IMUConfig.imuReversedFlags & IMU_REVERSE_GYRO_PR, IMUConfig.imuReversedFlags & IMU_REVERSE_GYRO_YAW);

  for (uint8_t axis=0; axis<3; axis++) {

        // 3) Filter.

    tempOffsetGyro[axis] = (gyro_PID[axis] * (IMUConfig.gyroPIDFilterConstant - 1) + tempOffsetGyro[axis]) / IMUConfig.gyroPIDFilterConstant;

    // 4) Measure noise.

    measureNoise(tempOffsetGyro[axis], &gyroNoisePeak[axis], GYRO_NOISE_MEASUREMENT_DAMPING);

    // 5) Differential measurement.

    // TODO: Examine effects of overruns here, they are quite possible.

    int16_t diff = tempOffsetGyro[axis] - gyro_PID[axis];

    gyroD[axis] -= gyroDWindow[axis][gyroDWindowIdx];

    gyroD[axis] += diff;

    gyroDWindow[axis][gyroDWindowIdx] = diff;

    // 6) Done.

    gyro_PID[axis] = tempOffsetGyro[axis];

    // Prepare tempOffsetGyro for next calculation below...

    tempOffsetGyro[axis] = (rawGyroValue(axis) - gyroOffset.offsets[axis]);

  }

  /*

   * Now process the data for attitude angles.

   */

  rotate(tempOffsetGyro, IMUConfig.gyroQuadrant, IMUConfig.imuReversedFlags & IMU_REVERSE_GYRO_PR, IMUConfig.imuReversedFlags & IMU_REVERSE_GYRO_YAW);

  // dampenGyroActivity();

  gyro_ATT[PITCH] = tempOffsetGyro[PITCH];

  gyro_ATT[ROLL] = tempOffsetGyro[ROLL];

  gyro_ATT[YAW] = tempOffsetGyro[YAW];

  if (++gyroDWindowIdx >= IMUConfig.gyroDWindowLength) {

      gyroDWindowIdx = 0;

  }

}

/*

// probably wanna aim at 1/10 m/s/unit.

#define LOG_AIRSPEED_FACTOR 0

void analog_updateAirspeed(void) {

  uint16_t rawAirpressure = ADSensorInputs[AD_AIRPRESSURE];

  int16_t temp = airpressureOffset - rawAirPressure;

//   airpressure -= airpressureWindow[airpressureWindowIdx];

//  airpressure += temp;

//  airpressureWindow[airpressureWindowIdx] = temp;

//  airpressureWindowIdx++;

//  if (airpressureWindowIdx == AIRPRESSURE_WINDOW_LENGTH) {

//        airpressureWindowIdx = 0;

//  }

#define AIRPRESSURE_FILTER 16

  airpressure = ((int32_t)airpressure * (AIRPRESSURE_FILTER-1) + (AIRPRESSURE_FILTER/2) + temp) / AIRPRESSURE_FILTER;

  uint16_t p2 = (airpressure<0) ? 0 : airpressure;

  airspeedVelocity = (staticParams.airspeedCorrection * isqrt16(p2)) >> LOG_AIRSPEED_FACTOR;

  debugOut.analog[17] = airpressure;

  debugOut.analog[18] = airpressureOffset;

  debugOut.analog[19] = airspeedVelocity;

  isFlying = 0; //(airspeedVelocity >= staticParams.isFlyingThreshold);

}

*/

void analog_updateBatteryVoltage(void) {

  // Battery. The measured value is: (V * 1k/11k)/3v * 1024 = 31.03 counts per volt (max. measurable is 33v).

  // This is divided by 3 --> 10.34 counts per volt.

  UBat = (3 * UBat + ADSensorInputs[AD_UBAT] / 3) / 4;

}

void analog_update(void) {

  analog_updateGyros();

  // analog_updateAccelerometers();

  // analog_updateAirspeed();

  analog_updateBatteryVoltage();

#ifdef USE_MK3MAG

  magneticHeading = volatileMagneticHeading;

#endif

}

void analog_setNeutral() {

        twimaster_setNeutral();

  if (gyroOffset_readFromEEProm()) {

    printf("gyro offsets invalid%s",recal);

    gyroOffset.offsets[PITCH] = gyroOffset.offsets[ROLL] = 0;

    gyroOffset.offsets[YAW] = 0;

  }

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

  for (uint8_t i=PITCH; i<=YAW; i++) {

          gyroNoisePeak[i] = 0;

          gyroD[i] = 0;

          for (uint8_t j=0; j<GYRO_D_WINDOW_LENGTH; j++) {

                  gyroDWindow[i][j] = 0;

          }

  }

  // Setting offset values has an influence in the analog.c ISR

  // Therefore run measurement for 100ms to achive stable readings

  delay_ms_with_adc_measurement(100, 0);

  // gyroActivity = 0;

}

void analog_calibrate(void) {

#define OFFSET_CYCLES 120

  uint8_t i, axis;

  int32_t offsets[4] = { 0, 0, 0, 0};

  // determine gyro bias by averaging (requires that the copter does not rotate around any axis!)

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

    delay_ms_with_adc_measurement(10, 1);

    for (axis = PITCH; axis <= YAW; axis++) {

      offsets[axis] += rawGyroValue(axis);

    }

    // offsets[3] += ADSensorInputs[AD_AIRPRESSURE];

  }

  for (axis = PITCH; axis <= YAW; axis++) {

    gyroOffset.offsets[axis] = (offsets[axis] + OFFSET_CYCLES / 2) / OFFSET_CYCLES;

  }

  /*

  airpressureOffset = (offsets[3] + OFFSET_CYCLES / 2) / OFFSET_CYCLES;

  int16_t min = 200;

  int16_t max = 1024-200;

  if(airpressureOffset < min || airpressureOffset > max)

    versionInfo.hardwareErrors[0] |= FC_ERROR0_PRESSURE;

  */

  gyroOffset_writeToEEProm();

  airpressureOffset_writeToEEProm();

  startAnalogConversionCycle();

}