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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;
*/
}