stub hella level sensor

firmware/controllers/sensors/hella_oil_level.cpp

@@ -0,0 +1,94 @@
+#include "pch.h"
+
+#include "hella_oil_level.h"
+
+static void hellaSensorExtiCallback(void* arg, efitick_t nowNt) {
+	reinterpret_cast<HellaOilLevelSensor*>(arg)->onEdge(nowNt);
+}
+
+void HellaOilLevelSensor::init(brain_pin_e pin) {
+	if (!isBrainPinValid(pin)) {
+		return;
+	}
+
+	m_pin = pin;
+
+#if EFI_PROD_CODE
+	efiExtiEnablePin(getSensorName(), pin, 
+		PAL_EVENT_MODE_BOTH_EDGES,
+		hellaSensorExtiCallback, reinterpret_cast<void*>(this));
+#endif // EFI_PROD_CODE
+
+	Register();
+}
+
+void HellaOilLevelSensor::onEdge(efitick_t nowNt) {
+	if (efiReadPin(m_pin)) {
+		// Start pulse width timing at the rising edge
+		m_pulseTimer.reset(nowNt);
+
+		float timeBetweenPulses = m_betweenPulseTimer.getElapsedSecondsAndReset(nowNt);
+
+		if (timeBetweenPulses > 0.89 * 0.780 && timeBetweenPulses < 1.11 * 0.780) {
+			// 780ms nominal between Diag and next Temp pulse start, +-10%
+
+			// This was the "long gap" break, next pulse is temperature.
+			m_nextPulse = NextPulse::Temp;
+		} else if (timeBetweenPulses > 0.89 * 0.110 && timeBetweenPulses < 1.11 * 0.110) {
+			// 110ms nominal between each pulse (other than break)
+
+			// Advance the state machine to decode the next pulse in the sequence
+			switch (m_nextPulse) {
+				case NextPulse::Temp:
+					m_nextPulse = NextPulse::Level;
+					break;
+				case NextPulse::Level:
+					m_nextPulse = NextPulse::Diag;
+					break;
+				default:
+					// We don't know how we got here, reset to safe state
+					m_nextPulse = NextPulse::None;
+					break;
+			}
+		} else {
+			// The break was too long, ignore it for now.
+			m_nextPulse = NextPulse::None;
+		}
+	} else {
+		// Stop timing at the falling edge
+		float lastPulseMs = 1000 * m_pulseTimer.getElapsedSeconds(nowNt);
+
+		if (m_nextPulse == NextPulse::Diag) {
+			// TODO: decode diag pulse?
+			return;
+		} else if (m_nextPulse = NextPulse::Temp) {
+			// 22ms = Short circuit temp sensor
+			// 23ms = -40C
+			// 87ms = 160C
+			// 88ms = Temp sensor defective
+
+			if (lastPulseMs < 22.8) {
+				// Short circuit
+				// invalidate(UnexpectedCode::Low);
+			} else if (lastPulseMs > 87.2) {
+				// Defective
+				// invalidate(UnexpectedCode::High);
+			} else {
+				float tempC = interpolateClamped(23, -40, 87, 160, lastPulseMs);
+				// setValidValue(tempC, nowNt);
+			}
+		} else if (m_nextPulse = NextPulse::Level) {
+			// 22ms = Unreliable signal
+			// 23ms = level 0mm
+			// 87.86ms = level 150mm
+
+			if (lastPulseMs < 22.8f) {
+				// Unreliable
+				invalidate(UnexpectedCode::Low);
+			} else {
+				float levelMm = interpolateClamped(23, 0, 87.86, 150, lastPulseMs);
+				setValidValue(levelMm, nowNt);
+			}
+		}
+	}
+}

firmware/controllers/sensors/hella_oil_level.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "stored_value_sensor.h"
+
+class HellaOilLevelSensor : public StoredValueSensor {
+public:
+	HellaOilLevelSensor(SensorType type) : StoredValueSensor(type, MS2NT(2000)) {}
+
+	void init(brain_pin_e pin);
+
+	void onEdge(efitick_t nowNt);
+
+private:
+	brain_pin_e m_pin = Gpio::Unassigned;
+
+	// Measures the width of positive pulses (rising -> falling)
+	Timer m_pulseTimer;
+
+	// Measures the time between pulses (rising -> rising)
+	Timer m_betweenPulseTimer;
+
+	enum class NextPulse { None, Temp, Level, Diag };
+	NextPulse m_nextPulse = NextPulse::None;
+};

firmware/controllers/sensors/sensors.mk

@@ -16,6 +16,7 @@ CONTROLLERS_SENSORS_SRC_CPP = \
 	$(PROJECT_DIR)/controllers/sensors/redundant_sensor.cpp \
 	$(PROJECT_DIR)/controllers/sensors/redundant_ford_tps.cpp \
 	$(PROJECT_DIR)/controllers/sensors/frequency_sensor.cpp \
+	$(PROJECT_DIR)/controllers/sensors/hella_oil_level.cpp \
 	$(PROJECT_DIR)/controllers/sensors/impl/software_knock.cpp \
 	$(PROJECT_DIR)/controllers/sensors/converters/linear_func.cpp \
 	$(PROJECT_DIR)/controllers/sensors/converters/resistance_func.cpp \