82 lines
1.7 KiB
C++
82 lines
1.7 KiB
C++
/*
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* @file tachometer.cpp
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* @brief This is about driving external analog tachometers
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*
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* This implementation produces one pulse per engine cycle
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*
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* @date Aug 18, 2015
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* @author Andrey Belomutskiy, (c) 2012-2020
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*/
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#include "pch.h"
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#include "tachometer.h"
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static SimplePwm tachControl("tach");
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static float tachFreq;
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static float duty;
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#if EFI_UNIT_TEST
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float getTachFreq() {
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return tachFreq;
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}
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float getTachDuty() {
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return duty;
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}
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#endif
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static bool tachHasInit = false;
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void tachUpdate() {
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// Only do anything if tach enabled
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if (!tachHasInit) {
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return;
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}
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// How many tach pulse periods do we have?
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int periods = engineConfiguration->tachPulsePerRev;
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if (periods == 0 || periods > 10) {
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firmwareError(ObdCode::CUSTOM_ERR_6709, "Invalid tachometer pulse per rev: %d", periods);
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return;
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}
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// What is the angle per tach output period?
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float cycleTimeMs = 60000.0f / Sensor::getOrZero(SensorType::Rpm);
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float periodTimeMs = cycleTimeMs / periods;
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tachFreq = 1000.0f / periodTimeMs;
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if (engineConfiguration->tachPulseDurationAsDutyCycle) {
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// Simple case - duty explicitly set
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duty = engineConfiguration->tachPulseDuractionMs;
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} else {
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// Constant high-time mode - compute the correct duty cycle
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duty = engineConfiguration->tachPulseDuractionMs / periodTimeMs;
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}
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// In case Freq is under 1Hz, we stop pwm to avoid warnings!
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if (tachFreq < 1) {
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tachFreq = NAN;
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}
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tachControl.setSimplePwmDutyCycle(duty);
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tachControl.setFrequency(tachFreq);
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}
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void initTachometer() {
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tachHasInit = false;
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if (!isBrainPinValid(engineConfiguration->tachOutputPin)) {
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return;
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}
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startSimplePwm(&tachControl,
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"Tachometer",
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&engine->scheduler,
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&enginePins.tachOut,
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NAN, 0.1f);
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tachHasInit = true;
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}
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