ResistanceFunc Class Reference

#include <resistance_func.h>

Inheritance diagram for ResistanceFunc:

Collaboration diagram for ResistanceFunc:

Public Member Functions
void	configure (float supplyVoltage, float pullupResistor, bool isPulldown)
SensorResult	convert (float inputValue) const override
void	showInfo (float testInputValue) const override
Public Member Functions inherited from SensorConverter
	SensorConverter (const SensorConverter &)=delete
	SensorConverter ()=default

Private Attributes
float	m_supplyVoltage = 5.0f
float	m_pullupResistor = 1000.0f
bool	m_isPulldown = false

Detailed Description

Author

Matthew Kennedy, (c) 2019

A function to convert input voltage to resistance in a voltage divider. Configured with the value of the pullup resistor, and the voltage to which it's connected.

Definition at line 13 of file resistance_func.h.

Member Function Documentation

configure()

void ResistanceFunc::configure	(	float	supplyVoltage,
		float	pullupResistor,
		bool	isPulldown
	)

Author

Matthew Kennedy, (c) 2019

Definition at line 7 of file resistance_func.cpp.

                                                                                         {
    m_pullupResistor = pullupResistor;
    m_supplyVoltage = supplyVoltage;
    m_isPulldown = isPulldown;
}

Referenced by initRangeSensors().

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convert()

SensorResult ResistanceFunc::convert ( float  inputValue ) const

overridevirtual

Implements SensorConverter.

Definition at line 13 of file resistance_func.cpp.

                                                    {
    // If the voltage is very low, the sensor is a dead short.
    if (raw < 0.05f) {
        return UnexpectedCode::Low;
    }
 
    // If the voltage is very high (98% VCC), the sensor is open circuit.
    if (raw > (m_supplyVoltage * 0.98f)) {
        return UnexpectedCode::High;
    }
 
    if (m_isPulldown) {
        // If the sensor is on the high side (fixed resistor is pulldown),
        // invert the voltage so the math comes out correctly
        raw = m_supplyVoltage - raw;
    }
 
    // Voltage is in a sensible range - convert
    float resistance = m_pullupResistor / (m_supplyVoltage / raw - 1);
 
    return resistance;
}

Referenced by showInfo().

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showInfo()

void ResistanceFunc::showInfo ( float  testInputValue ) const

overridevirtual

Reimplemented from SensorConverter.

Definition at line 93 of file sensor_info_printing.cpp.

                                                        {
    const auto result = convert(testInputValue);
    efiPrintf("    %.2f volts -> %.1f ohms with supply voltage %.2f and pullup %.1f.", testInputValue, result.Value, m_supplyVoltage, m_pullupResistor);
}

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Field Documentation

m_isPulldown

bool ResistanceFunc::m_isPulldown = false

private

Definition at line 24 of file resistance_func.h.

Referenced by configure(), and convert().

m_pullupResistor

float ResistanceFunc::m_pullupResistor = 1000.0f

private

Definition at line 23 of file resistance_func.h.

Referenced by configure(), convert(), and showInfo().

m_supplyVoltage

float ResistanceFunc::m_supplyVoltage = 5.0f

private

Definition at line 22 of file resistance_func.h.

Referenced by configure(), convert(), and showInfo().

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The documentation for this class was generated from the following files:

• controllers/sensors/converters/resistance_func.h
• controllers/sensors/converters/resistance_func.cpp
• controllers/sensors/sensor_info_printing.cpp