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#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>

#include "analog.h"
#include "attitude.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 DebugOut.Digital
#include "output.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[3];
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
 */

volatile uint8_t rangewidth = 106;

// Direct from sensor, irrespective of range.
// volatile uint16_t rawAirPressure;

// Value of 2 samples, with range.
volatile uint16_t simpleAirPressure;

// Value of AIRPRESSURE_SUMMATION_FACTOR samples, with range, filtered.
volatile int32_t filteredAirPressure;

// Partial sum of AIRPRESSURE_SUMMATION_FACTOR samples.
volatile int32_t airPressureSum;

// The number of samples summed into airPressureSum so far.
volatile uint8_t pressureMeasurementCount;

/*
 * 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 8, measure Z acc.
  AD_GYRO_PITCH, AD_GYRO_ROLL, AD_GYRO_YAW, // at 11, finish yaw gyro
 
  AD_ACC_PITCH,   // at 12, finish pitch axis acc.
  AD_ACC_ROLL,    // at 13, finish roll axis acc.
  AD_AIRPRESSURE, // at 14, finish air pressure.
 
  AD_GYRO_PITCH,  // at 15, finish pitch gyro
  AD_GYRO_ROLL,   // at 16, finish roll gyro
  AD_UBAT         // at 17, 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;
        }
}

/*
 * Min.: 0
 * Max: About 106 * 240 + 2047 = 27487; it is OK with just a 16 bit type.
 */

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

void transformPRGyro(int16_t* result) {
  static const uint8_t tab[] = {1,1,0,0-1,-1,-1,0,1};
  int8_t pp = GYROS_REVERSED ? tab[(GYRO_QUADRANT+4)%8] : tab[GYRO_QUADRANT];
  int8_t pr = tab[(GYRO_QUADRANT+2)%8];
  int8_t rp = GYROS_REVERSED ? tab[(GYRO_QUADRANT+2)%8] : tab[(GYRO_QUADRANT+6)%8];
  int8_t rr = tab[GYRO_QUADRANT];
 
  int16_t temp = result[0];
  result[0] = pp*result[0] + pr*result[1];
  result[1] = rp*temp + rr*result[1];
}

/*****************************************************
 * 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 uint16_t pressureAutorangingWait = 25;
        uint16_t rawAirPressure;
        uint8_t i, axis;
        int16_t newrange;

        // for various filters...
        int16_t tempOffsetGyro[2];

        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 8: // Z acc
                if (Z_ACC_REVERSED)
                        acc[Z] = accOffset[Z] - sensorInputs[AD_ACC_Z];
                else
                        acc[Z] = sensorInputs[AD_ACC_Z] - accOffset[Z];

                /*
        stronglyFilteredAcc[Z] =
            (stronglyFilteredAcc[Z] * 99 + acc[Z] * 10) / 100;
        */


                break;

        case 11: // yaw gyro
                rawGyroSum[YAW] = sensorInputs[AD_GYRO_YAW];
                if (YAW_REVERSED)
                  tempOffsetGyro[0] = gyroOffset[YAW] - sensorInputs[AD_GYRO_YAW];
                else
                  tempOffsetGyro[0] = sensorInputs[AD_GYRO_YAW] - gyroOffset[YAW];
                gyroD[YAW] = (gyroD[YAW] * (GYROS_D_FILTER - 1) + (tempOffsetGyro[0] - yawGyro)) / GYROS_D_FILTER;
                yawGyro = tempOffsetGyro[0];
                break;         
    case 13: // roll axis acc.
            /*            
            for (axis=0; axis<2; axis++) {
                if (ACC_REVERSED[axis])
                        tempSensor[axis] = accOffset[axis] - sensorInputs[AD_ACC_PITCH-axis];
                else
                        tempSensor[axis] = sensorInputs[AD_ACC_PITCH-axis] - accOffset[axis];
            }
            if (AXIS_TRANSFORM) {
                acc[PITCH] = tempSensor[PITCH] + tempSensor[ROLL];
                acc[ROLL] = tempSensor[ROLL] - tempSensor[PITCH];
            } else {
                acc[PITCH] = tempSensor[PITCH];
                acc[ROLL] = tempSensor[ROLL];
            }
            */


            // We have no sensor installed...
            acc[PITCH] = acc[ROLL] = 0;

            for (axis=0; axis<2; axis++) {
        filteredAcc[axis] =
                    (filteredAcc[axis] * (ACC_FILTER - 1) + acc[axis]) / ACC_FILTER;
                measureNoise(acc[axis], &accNoisePeak[axis], 1);
            }
                break;

        case 14: // air pressure
                if (pressureAutorangingWait) {
                        //A range switch was done recently. Wait for steadying.
                        pressureAutorangingWait--;
                        DebugOut.Analog[27] = (uint16_t) OCR0A;
                        DebugOut.Analog[31] = simpleAirPressure;
                        break;
                }

                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.
                        newrange = OCR0A - (MAX_RAWPRESSURE - MIN_RAWPRESSURE) / (rangewidth * 4); // 4; // (MAX_RAWPRESSURE - rawAirPressure) / (rangewidth * 2) + 1;
                        if (newrange > MIN_RANGES_EXTRAPOLATION) {
                                pressureAutorangingWait = (OCR0A - newrange) * AUTORANGE_WAIT_FACTOR; // = OCRA0 - OCRA0 +
                                OCR0A = newrange;
                        } else {
                                if (OCR0A) {
                                        OCR0A--;
                                        pressureAutorangingWait = AUTORANGE_WAIT_FACTOR;
                                }
                        }
                } else if (rawAirPressure > MAX_RAWPRESSURE) {
                        // value is too high, so increase voltage on the op amp minus input, making the value lower.
                        // If near the end, make a limited increase
                        newrange = OCR0A + (MAX_RAWPRESSURE - MIN_RAWPRESSURE) / (rangewidth * 4); // 4;  // (rawAirPressure - MIN_RAWPRESSURE) / (rangewidth * 2) - 1;
                        if (newrange < MAX_RANGES_EXTRAPOLATION) {
                                pressureAutorangingWait = (newrange - OCR0A) * AUTORANGE_WAIT_FACTOR;
                                OCR0A = newrange;
                        } else {
                                if (OCR0A < 254) {
                                        OCR0A++;
                                        pressureAutorangingWait = AUTORANGE_WAIT_FACTOR;
                                }
                        }
                }

                // Even if the sample is off-range, use it.
                simpleAirPressure = getSimplePressure(rawAirPressure);
                DebugOut.Analog[27] = (uint16_t) OCR0A;
                DebugOut.Analog[31] = simpleAirPressure;

                if (simpleAirPressure < MIN_RANGES_EXTRAPOLATION * rangewidth) {
                        // Danger: pressure near lower end of range. If the measurement saturates, the
                        // copter may climb uncontrolledly... Simulate a drastic reduction in pressure.
                        DebugOut.Digital[1] |= DEBUG_SENSORLIMIT;
                        airPressureSum += (int16_t) MIN_RANGES_EXTRAPOLATION * rangewidth
                                        + (simpleAirPressure - (int16_t) MIN_RANGES_EXTRAPOLATION
                                                        * rangewidth) * PRESSURE_EXTRAPOLATION_COEFF;
                } else if (simpleAirPressure > MAX_RANGES_EXTRAPOLATION * rangewidth) {
                        // Danger: pressure near upper end of range. If the measurement saturates, the
                        // copter may descend uncontrolledly... Simulate a drastic increase in pressure.
                        DebugOut.Digital[1] |= DEBUG_SENSORLIMIT;
                        airPressureSum += (int16_t) MAX_RANGES_EXTRAPOLATION * rangewidth
                                        + (simpleAirPressure - (int16_t) MAX_RANGES_EXTRAPOLATION
                                                        * rangewidth) * PRESSURE_EXTRAPOLATION_COEFF;
                } else {
                        // normal case.
                        // If AIRPRESSURE_SUMMATION_FACTOR is an odd number we only want to add half the double sample.
                        // The 2 cases above (end of range) are ignored for this.
                        DebugOut.Digital[1] &= ~DEBUG_SENSORLIMIT;
                        if (pressureMeasurementCount == AIRPRESSURE_SUMMATION_FACTOR - 1)
                                airPressureSum += simpleAirPressure / 2;
                        else
                                airPressureSum += simpleAirPressure;
                }

                // 2 samples were added.
                pressureMeasurementCount += 2;
                if (pressureMeasurementCount >= AIRPRESSURE_SUMMATION_FACTOR) {
                        filteredAirPressure = (filteredAirPressure * (AIRPRESSURE_FILTER - 1)
                                        + airPressureSum + AIRPRESSURE_FILTER / 2) / AIRPRESSURE_FILTER;
                        pressureMeasurementCount = airPressureSum = 0;
                }

                break;

    case 16: // pitch and roll gyro.
            for (axis=0; axis<2; axis++) {
                tempOffsetGyro[axis] = rawGyroSum[axis] = sensorInputs[AD_GYRO_PITCH - axis];
                // 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 (tempOffsetGyro[axis] < SENSOR_MIN_PITCHROLL) {
                                DebugOut.Digital[0] |= DEBUG_SENSORLIMIT;
                                tempOffsetGyro[axis] = tempOffsetGyro[axis] * EXTRAPOLATION_SLOPE - EXTRAPOLATION_LIMIT;
                        } else if (tempOffsetGyro[axis] > SENSOR_MAX_PITCHROLL) {
                                DebugOut.Digital[0] |= DEBUG_SENSORLIMIT;
                                tempOffsetGyro[axis] = (tempOffsetGyro[axis] - SENSOR_MAX_PITCHROLL) * EXTRAPOLATION_SLOPE + SENSOR_MAX_PITCHROLL;
                        } else {
                                DebugOut.Digital[0] &= ~DEBUG_SENSORLIMIT;
                        }
                }

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

        // 2.1: Transform axis if configured to.
            transformPRGyro(tempOffsetGyro);

                // 3) Scale and filter.
            for (axis=0; axis<2; axis++) {
                tempOffsetGyro[axis] = (gyro_PID[axis] * (GYROS_PID_FILTER - 1) + tempOffsetGyro[axis]) / GYROS_PID_FILTER;

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

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

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

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

            for (axis=0; axis<2; axis++) {
              tempOffsetGyro[axis] = (rawGyroSum[axis] - gyroOffset[axis]) * GYRO_FACTOR_PITCHROLL;
            }

            transformPRGyro(tempOffsetGyro);
           
            // 2) Filter. This should really be quite unnecessary. The integration should gobble up any noise anyway and the values are not used for anything else.
            gyro_ATT[PITCH] = (gyro_ATT[PITCH] * (GYROS_ATT_FILTER - 1) + tempOffsetGyro[PITCH]) / GYROS_ATT_FILTER;
            gyro_ATT[ROLL] = (gyro_ATT[ROLL] * (GYROS_ATT_FILTER - 1) + tempOffsetGyro[ROLL]) / GYROS_ATT_FILTER;
            break;
           
        case 17:
                // 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 + sensorInputs[AD_UBAT] / 3) / 4;
                DebugOut.Analog[20] = UBat;
                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 };

        // Set the filters... to be removed again, once some good settings are found.
        GYROS_PID_FILTER = (staticParams.sensorFilterSettings & (0x7 & (1<<0))) + 1;
        GYROS_ATT_FILTER = 1;
        GYROS_D_FILTER =   (staticParams.sensorFilterSettings & (0x3 & (1<<4))) + 1;
        ACC_FILTER =       (staticParams.sensorFilterSettings & (0x3 & (1<<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(20);
                for (axis = PITCH; axis <= YAW; axis++) {
                        deltaOffsets[axis] += rawGyroSum[axis];
                }
        }

        for (axis = PITCH; axis <= YAW; axis++) {
                gyroOffset[axis] = (deltaOffsets[axis] + GYRO_OFFSET_CYCLES / 2) / GYRO_OFFSET_CYCLES;
                // DebugOut.Analog[20 + axis] = gyroOffset[axis];
        }

        // Noise is relativ 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);

        // Rough estimate. Hmm no nothing happens at calibration anyway.
        // airPressureSum = simpleAirPressure * (AIRPRESSURE_SUMMATION_FACTOR/2);
        // pressureMeasurementCount = 0;

        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 = PITCH; axis <= YAW; axis++) {
                        deltaOffset[axis] += acc[axis];
                }
        }

        for (axis = PITCH; 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 - 1024) / rangewidth) - 1;
         delay_ms_Mess(1000);

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

         #define PRESSURE_CAL_CYCLE_COUNT 5
         for (i=0; i<PRESSURE_CAL_CYCLE_COUNT; i++) {
         savedRawAirPressure = rawAirPressure;
         OCR0A+=2;
         delay_ms_Mess(500);
         // raw pressure will decrease.
         pressureDiff += (savedRawAirPressure - rawAirPressure);
         savedRawAirPressure = rawAirPressure;
         OCR0A-=2;
         delay_ms_Mess(500);
         // raw pressure will increase.
         pressureDiff += (rawAirPressure - savedRawAirPressure);
         }

         rangewidth = (pressureDiff + PRESSURE_CAL_CYCLE_COUNT * 2 * 2 - 1) / (PRESSURE_CAL_CYCLE_COUNT * 2 * 2);
         DebugOut.Analog[27] = rangewidth;
         */

}