rusefi-1/firmware/controllers/sensors/software_knock.cpp

#include "global.h"
#include "engine.h"
#include "biquad.h"
#include "perf_trace.h"
#include "thread_controller.h"
#include "software_knock.h"

#if EFI_SOFTWARE_KNOCK

EXTERN_ENGINE;

#include "knock_config.h"

adcsample_t sampleBuffer[2000];
Biquad knockFilter;

static volatile bool knockIsSampling = false;
static volatile bool knockNeedsProcess = false;
static volatile size_t sampleCount = 0;

binary_semaphore_t knockSem;

static void completionCallback(ADCDriver* adcp, adcsample_t*, size_t) {
	palClearPad(GPIOD, 2);

	if (adcp->state == ADC_COMPLETE) {
		knockNeedsProcess = true;

		// Notify the processing thread that it's time to process this sample
		chSysLockFromISR();
		chBSemSignalI(&knockSem);
		chSysUnlockFromISR();
	}
}

static void errorCallback(ADCDriver*, adcerror_t err) {
}

static const ADCConversionGroup adcConvGroup = { FALSE, 1, &completionCallback, &errorCallback,
	0,
	ADC_CR2_SWSTART,
	ADC_SMPR1_SMP_AN14(KNOCK_SAMPLE_TIME), // sample times for channels 10...18
	0,

	0,	// htr
	0,	// ltr

	0,	// sqr1
	0,	// sqr2
	ADC_SQR3_SQ1_N(KNOCK_ADC_CH1)
};

void startKnockSampling(uint8_t cylinderIndex) {
	if (!CONFIG(enableSoftwareKnock)) {
		return;
	}

	// Cancel if ADC isn't ready
	if (!((KNOCK_ADC.state == ADC_READY) ||
			(KNOCK_ADC.state == ADC_COMPLETE) ||
			(KNOCK_ADC.state == ADC_ERROR))) {
		return;
	}

	// If there's pending processing, skip this event
	if (knockNeedsProcess) {
		return;
	}

	// Sample for 45 degrees
	float samplingSeconds = ENGINE(rpmCalculator).oneDegreeUs * 45 * 1e-6;
	constexpr int sampleRate = KNOCK_SAMPLE_RATE;
	sampleCount = 0xFFFFFFFE & static_cast<size_t>(clampF(100, samplingSeconds * sampleRate, efi::size(sampleBuffer)));

	adcStartConversionI(&KNOCK_ADC, &adcConvGroup, sampleBuffer, sampleCount);
}

class KnockThread : public ThreadController<256> {
public:
	KnockThread() : ThreadController("knock", NORMALPRIO - 10) {}
	void ThreadTask() override;
};

KnockThread kt;

void initSoftwareKnock() {
	chBSemObjectInit(&knockSem, TRUE);

	if (CONFIG(enableSoftwareKnock)) {
		knockFilter.configureBandpass(KNOCK_SAMPLE_RATE, 1000 * CONFIG(knockBandCustom), 3);
		adcStart(&KNOCK_ADC, nullptr);

		efiSetPadMode("knock ch1", KNOCK_PIN_CH1, PAL_MODE_INPUT_ANALOG);
		efiSetPadMode("knock ch2", KNOCK_PIN_CH2, PAL_MODE_INPUT_ANALOG);

		kt.Start();
	}
}

void processLastKnockEvent() {
	if (!knockNeedsProcess) {
		return;
	}

	float sumSq = 0;

	constexpr float ratio = 3.3f / 4095.0f;

	size_t localCount = sampleCount;

	// Prepare the steady state at vcc/2 so that there isn't a step
	// when samples begin
	knockFilter.cookSteadyState(3.3f / 2);

	// Compute the sum of squares
	for (size_t i = 0; i < localCount; i++)
	{
		float volts = ratio * sampleBuffer[i];

		float filtered = knockFilter.filter(volts);

		sumSq += filtered * filtered;
	}

	// mean of squares (not yet root)
	float meanSquares = sumSq / localCount;

	// RMS
	float db = 10 * log10(meanSquares);

	tsOutputChannels.knockLevel = db;

	knockNeedsProcess = false;
}

void KnockThread::ThreadTask() {
	while(1) {
		chBSemWait(&knockSem);

		ScopePerf perf(PE::SoftwareKnockProcess);
		processLastKnockEvent();
	}
}

#endif // EFI_SOFTWARE_KNOCK