#include <trigger_input_adc.h>

Collaboration diagram for TriggerAdcDetector:

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Public Member Functions
void	init ()

void	reset ()

void	digitalCallback (efitick_t stamp, bool isPrimary, bool rise)

void	analogCallback (efitick_t stamp, triggerAdcSample_t value)

void	setWeakSignal (bool isWeak)

Data Fields
triggerAdcSample_t	adcDefaultThreshold {}

triggerAdcSample_t	adcMinThreshold {}

triggerAdcSample_t	adcMaxThreshold {}

float	triggerInputDividerCoefficient {}

float	triggerAdcITermCoef = 1600.0f

float	triggerAdcITermMin = 3.125e-8f

int	transitionCooldown = 5

int	analogToDigitalTransitionCnt {}

int	digitalToAnalogTransitionCnt {}

triggerAdcMode_t	curAdcMode = TRIGGER_ADC_NONE

float	adcThreshold = adcDefaultThreshold

float	triggerAdcITerm = triggerAdcITermMin

triggerAdcSample_t	switchingThresholdLow = 0

triggerAdcSample_t	switchingThresholdHigh = 0

efidur_t	minDeltaTimeForStableAdcDetectionNt = 0

efidur_t	stampCorrectionForAdc = 0

int	switchingCnt = 0

int	switchingTeethCnt = 0

int	prevValue = 0

efitick_t	prevStamp = 0

bool	isSignalWeak = true

int	zeroThreshold = 0

int	minDeltaThresholdWeakSignal = 0

int	minDeltaThresholdStrongSignal = 0

int	minDeltaThresholdCntPos = 0

int	minDeltaThresholdCntNeg = 0

int	integralSum = 0

int	transitionCooldownCnt = 0

int	modeSwitchCnt = 0

Detailed Description

Definition at line 15 of file trigger_input_adc.h.

Member Function Documentation

◆ analogCallback()

void TriggerAdcDetector::analogCallback	(	efitick_t	stamp,
		triggerAdcSample_t	value
	)

Definition at line 278 of file trigger_input_adc.cpp.

                                                                                 {
#if ! EFI_SIMULATOR && ((HAL_TRIGGER_USE_ADC && HAL_USE_ADC) || EFI_UNIT_TEST)
    if (curAdcMode != TRIGGER_ADC_ADC) {
        return;
    }
 
#ifdef TRIGGER_ADC_DUMP_BUF
    dumpBuf[dumpBufCnt] = value;
    dumpBufCnt = (dumpBufCnt + 1) % dumpBufNum;
#endif /* TRIGGER_ADC_DUMP_BUF */
 
    // <1V or >4V?
    if (value >= switchingThresholdHigh || value <= switchingThresholdLow) {
        switchingCnt++;
    } else {
        //switchingCnt = 0;
        switchingCnt = maxI(switchingCnt - 1, 0);
    }
 
    int delta = value - adcThreshold;
    int aDelta = absI(delta);
    if (isSignalWeak) {
        // todo: detect if the sensor is disconnected (where the signal is always near 'ADC_MAX_VALUE')
 
        // filter out low signals (noise)
        if (delta >= minDeltaThresholdWeakSignal) {
            minDeltaThresholdCntPos++;
        }
        if (delta <= -minDeltaThresholdWeakSignal) {
            minDeltaThresholdCntNeg++;
        }
    } else {
        // we just had a strong signal, let's reset the counter
        if (delta >= minDeltaThresholdWeakSignal) {
            minDeltaThresholdCntPos = DELTA_THRESHOLD_CNT_HIGH;
        }
        if (delta <= -minDeltaThresholdWeakSignal) {
            minDeltaThresholdCntNeg = DELTA_THRESHOLD_CNT_HIGH;
        }
        minDeltaThresholdCntPos--;
        minDeltaThresholdCntNeg--;
        // we haven't seen the strong signal (pos or neg) for too long, maybe it's lost or too weak?
        if (minDeltaThresholdCntPos <= 0 || minDeltaThresholdCntNeg <= 0) {
            // reset to the weak signal mode
            reset();
            return;
        }
    }
 
    // the threshold should always correspond to the averaged signal.
    integralSum += delta;
    // we need some limits for the integral sum
    // we use a simple I-regulator to move the threshold
    adcThreshold += (float)integralSum * triggerAdcITerm;
    // limit the threshold for safety
    adcThreshold = maxF(minF(adcThreshold, adcMaxThreshold), adcMinThreshold);
 
    // now to the transition part... First, we need a cooldown to pre-filter the transition noise
    if (transitionCooldownCnt-- < 0)
        transitionCooldownCnt = 0;
 
    // we need at least 2 different measurements to detect a transition
    if (prevValue == 0) {
        // we can take the measurement only from outside the dead-zone
        if (aDelta > minDeltaThresholdWeakSignal) {
            prevValue = (delta > 0) ? 1 : -1;
        } else {
            return;
        }
    }
 
    if (isSignalWeak) {
         if (minDeltaThresholdCntPos >= DELTA_THRESHOLD_CNT_LOW && minDeltaThresholdCntNeg >= DELTA_THRESHOLD_CNT_LOW) {
            // ok, now we have a legit strong signal, let's restore the threshold
            isSignalWeak = false;
            integralSum = 0;
            zeroThreshold = minDeltaThresholdStrongSignal;
         } else {
            // we cannot trust the weak signal!
            return;
         }
    }
 
    if (transitionCooldownCnt <= 0) {
        // detect the edge
        int transition = 0;
        if (delta > zeroThreshold && prevValue == -1)   {
            // a rising transition found!
            transition = 1;
        }
        else if (delta <= -zeroThreshold && prevValue == 1) {
            // a falling transition found!
            transition = -1;
        }
        else {
            return; // both are positive/negative/zero: not interested!
        }
 
        onTriggerChanged(stamp - stampCorrectionForAdc, true, transition == 1);
        // let's skip some nearest possible measurements:
        // the transition cannot be SO fast, but the jitter can!
        transitionCooldownCnt = transitionCooldown;
 
        // it should not accumulate too much
        integralSum = 0;
#if 0
        // update triggerAdcITerm
        efitimeus_t deltaTimeUs = NT2US(stamp - prevStamp);
        if (deltaTimeUs > 200) {    // 200 us = ~2500 RPM (we don't need this correction for large RPM)
            triggerAdcITerm = 1.0f / (triggerAdcITermCoef * deltaTimeUs);
            triggerAdcITerm = std::max(triggerAdcITerm, triggerAdcITermMin);
        }
#endif // 0
 
        prevValue = transition;
    }
 
#ifdef EFI_SHAFT_POSITION_INPUT
    if (switchingCnt >= analogToDigitalTransitionCnt) {
        switchingCnt = 0;
        // we need at least 3 high-signal teeth to be certain!
        if (switchingTeethCnt++ > 3) {
            switchingTeethCnt = 0;
 
            setTriggerAdcMode(TRIGGER_ADC_EXTI);
 
            // we don't want to loose the signal on return
            minDeltaThresholdCntPos = DELTA_THRESHOLD_CNT_HIGH;
            minDeltaThresholdCntNeg = DELTA_THRESHOLD_CNT_HIGH;
            // we want to reset the thresholds on return
            zeroThreshold = minDeltaThresholdStrongSignal;
            adcThreshold = adcDefaultThreshold;
            // reset integrator
            triggerAdcITerm = triggerAdcITermMin;
            integralSum = 0;
            transitionCooldownCnt = 0;
            return;
        }
    } else {
        // we don't see "big teeth" anymore
        switchingTeethCnt = 0;
    }
#endif // EFI_SHAFT_POSITION_INPUT
 
    prevStamp = stamp;
#else
    UNUSED(stamp); UNUSED(value);
#endif // ! EFI_SIMULATOR && ((HAL_TRIGGER_USE_ADC && HAL_USE_ADC) || EFI_UNIT_TEST)
}

Referenced by triggerAdcCallback().

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◆ digitalCallback()

void TriggerAdcDetector::digitalCallback	(	efitick_t	stamp,
		bool	isPrimary,
		bool	rise
	)

Definition at line 244 of file trigger_input_adc.cpp.

                                                                                   {
#if !EFI_SIMULATOR && EFI_SHAFT_POSITION_INPUT
    if (curAdcMode != TRIGGER_ADC_EXTI) {
        return;
    }
 
    UNUSED(isPrimary);
 
    onTriggerChanged(stamp, isPrimary, rise);
 
#if (HAL_TRIGGER_USE_ADC && HAL_USE_ADC) || EFI_UNIT_TEST
    if ((stamp - prevStamp) > minDeltaTimeForStableAdcDetectionNt) {
        switchingCnt++;
    } else {
        switchingCnt = 0;
        switchingTeethCnt = 0;
    }
 
    if (switchingCnt >= digitalToAnalogTransitionCnt) {
        switchingCnt = 0;
        // we need at least 3 wide teeth to be certain!
        // we don't want to confuse them with a sync.gap
        if (switchingTeethCnt++ > 3) {
            switchingTeethCnt = 0;
            prevValue = rise ? 1: -1;
            setTriggerAdcMode(TRIGGER_ADC_ADC);
        }
    }
#endif // (HAL_TRIGGER_USE_ADC && HAL_USE_ADC) || EFI_UNIT_TEST
 
    prevStamp = stamp;
#endif // !EFI_SIMULATOR && EFI_SHAFT_POSITION_INPUT
}

Referenced by shaft_callback().

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◆ init()

void TriggerAdcDetector::init ( )

Definition at line 182 of file trigger_input_adc.cpp.

                              {
#if ! EFI_SIMULATOR
 
    // todo: move some of these to config
 
#if HAL_USE_ADC || EFI_UNIT_TEST
    // 4.7k||5.1k + 4.7k
    triggerInputDividerCoefficient = 1.52f; // = analogInputDividerCoefficient
 
    // we need to make at least minNumAdcMeasurementsPerTooth for 1 tooth (i.e. between two consequent events)
    const int minNumAdcMeasurementsPerTooth = 10; // for 60-2 wheel: 1/(10*2*60/10000/60) = 500 RPM
    minDeltaTimeForStableAdcDetectionNt = US2NT(US_PER_SECOND_LL * minNumAdcMeasurementsPerTooth * GPT_PERIOD_FAST / GPT_FREQ_FAST);
    // we assume that the transition occurs somewhere in the middle of the measurement period, so we take the half of it
    stampCorrectionForAdc = US2NT(US_PER_SECOND_LL * GPT_PERIOD_FAST / GPT_FREQ_FAST / 2);
 
    analogToDigitalTransitionCnt = 4;
    digitalToAnalogTransitionCnt = 4;
 
    // used to filter out low signals
    minDeltaThresholdWeakSignal = triggerVoltsToAdcDivided(0.05f);  // 50mV
    // we need to shift the default threshold even for strong signals because of the possible loss of the first tooth (after the sync)
    minDeltaThresholdStrongSignal = triggerVoltsToAdcDivided(0.04f);    // 5mV
 
    const triggerAdcSample_t adcDeltaThreshold = triggerVoltsToAdcDivided(0.25f);
    adcDefaultThreshold = triggerVoltsToAdcDivided(2.5f);   // this corresponds to VREF1 on Hellen boards
    adcMinThreshold = adcDefaultThreshold - adcDeltaThreshold;
    adcMaxThreshold = adcDefaultThreshold + adcDeltaThreshold;
 
    // these thresholds allow to switch from ADC mode to EXTI mode, indicating the clamping of the signal
    // they should exceed the MCU schmitt trigger thresholds (usually 0.3*Vdd and 0.7*Vdd)
    switchingThresholdLow = triggerVoltsToAdcDivided(1.0f);  // = 0.2*Vdd (<0.3*Vdd)
    switchingThresholdHigh = triggerVoltsToAdcDivided(4.0f); // = 0.8*Vdd (>0.7*Vdd)
#endif // HAL_USE_ADC || EFI_UNIT_TEST
 
    modeSwitchCnt = 0;
 
    reset();
#endif // ! EFI_SIMULATOR
}

Referenced by adcTriggerTurnOnInputPin().

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◆ reset()

void TriggerAdcDetector::reset ( )

Definition at line 222 of file trigger_input_adc.cpp.

                               {
    switchingCnt = 0;
    switchingTeethCnt = 0;
#if HAL_USE_ADC || EFI_UNIT_TEST
    // when the strong signal becomes weak, we want to ignore the increased noise
    // so we create a dead-zone between the pos. and neg. thresholds
    zeroThreshold = minDeltaThresholdWeakSignal / 2;
    triggerAdcITerm = triggerAdcITermMin;
 
    adcThreshold = adcDefaultThreshold;
 
    isSignalWeak = true;
    integralSum = 0;
    transitionCooldownCnt = 0;
    minDeltaThresholdCntPos = 0;
    minDeltaThresholdCntNeg = 0;
#endif // HAL_USE_ADC || EFI_UNIT_TEST
 
    prevValue = 0;  // not set
    prevStamp = 0;
}

Referenced by analogCallback(), and init().

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◆ setWeakSignal()

void TriggerAdcDetector::setWeakSignal ( bool isWeak )

Definition at line 428 of file trigger_input_adc.cpp.

                                                  {
#if HAL_USE_ADC || EFI_UNIT_TEST
    isSignalWeak = isWeak;
    if (!isSignalWeak) {
        minDeltaThresholdCntPos = minDeltaThresholdCntNeg = DELTA_THRESHOLD_CNT_LOW;
    } else {
        minDeltaThresholdCntPos = minDeltaThresholdCntNeg = 0;
    }
#endif // HAL_USE_ADC || EFI_UNIT_TEST
}