units.h File Reference

Integer conversions using scale & translate. More...

#include <stdint.h>

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Classes
struct	conversionFactor< TUser, TRaw >
	Scale and translate signed/unsigned values to convert between "raw" & "user" values. More...

Functions
static constexpr uint8_t	temperatureAddOffset (int16_t temp)
	Convert from a user temperature (-40, 215) to storage (0, 255)
static constexpr int16_t	temperatureRemoveOffset (uint8_t temp)
	Convert from a storage temperature (0, 255) to user (-40, 215)

Variables
Conversion factors
Note Since these are all constexpr, they should be zero overhead in time & space (unless we take the address of one of them)
static constexpr conversionFactor< uint16_t, uint8_t >	RPM_COARSE = { .scale=100U, .translate=0U }
	RPM stored as RPM/100. E.g. 2700 -> 27 -> 2700.
static constexpr conversionFactor< uint16_t, uint8_t >	RPM_MEDIUM = { .scale=10U, .translate=0U }
	RPM stored as RPM/10. E.g. 2700 -> 270 -> 2700.
static constexpr conversionFactor< uint16_t, uint8_t >	RPM_FINE = { .scale=5U, .translate=0U }
	RPM stored as RPM/5. E.g. 1300->260->1300.
static constexpr conversionFactor< uint32_t, uint8_t >	TIME_TENTH_MILLIS = { .scale=10000U, .translate=0U }
	Time values stored in 1/10th milliseconds I.e ms/10.
static constexpr conversionFactor< uint16_t, uint8_t >	TIME_TWENTY_MILLIS = { .scale=5U, .translate=0U }
	Time values stored in 20 milliseconds.
static constexpr conversionFactor< uint16_t, uint8_t >	TIME_TEN_MILLIS = { .scale=100U, .translate=0U }
	Time values stored in 10 milliseconds.
static constexpr conversionFactor< uint16_t, uint8_t >	MAP = { .scale=2U, .translate=0U }
	MAP values: kpa.
static constexpr conversionFactor< int16_t, uint8_t >	MAP_DOT = { .scale=10U, .translate=0U }
	MAP rate of change: kpa/s
static constexpr conversionFactor< int16_t, uint8_t >	TPS_DOT = { .scale=10U, .translate=0U }
	TPS rate of change: %/s.
static constexpr conversionFactor< uint16_t, uint8_t >	CRANKING_ENRICHMENT = { .scale=5U, .translate=0U }
	Cranking enrichment values range from 0% to 1275%.
static constexpr conversionFactor< int8_t, uint8_t >	IGNITION_ADVANCE_LARGE = { .scale=1U, .translate=-40 }
	Ignition values from the main spark table are offset 40 degrees downwards to allow for negative spark timing.
static constexpr conversionFactor< int8_t, uint8_t >	IGNITION_ADVANCE_SMALL = { .scale=1U, .translate=-15 }
	Ignition advance adjustments can use a smaller offset.
static constexpr conversionFactor< int16_t, uint8_t >	TEMPERATURE = { .scale=1U, .translate=-40 }
	All temperature measurements are stored offset by 40 degrees, to represent temperature ranges from -40 to 215.

Detailed Description

Integer conversions using scale & translate.

Function Documentation

temperatureAddOffset()

static constexpr uint8_t temperatureAddOffset ( int16_t  temp )

inlinestaticconstexpr

Convert from a user temperature (-40, 215) to storage (0, 255)

This is done often enough to warrant wrapping toRaw

Parameters

temp	Working temperature (-40, 215)

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temperatureRemoveOffset()

static constexpr int16_t temperatureRemoveOffset ( uint8_t  temp )

inlinestaticconstexpr

Convert from a storage temperature (0, 255) to user (-40, 215)

This is done often enough to warrant wrapping toUser

Parameters

temp	Storage temperature (0, 255)

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Variable Documentation

CRANKING_ENRICHMENT

constexpr conversionFactor<uint16_t, uint8_t> CRANKING_ENRICHMENT = { .scale=5U, .translate=0U }

staticconstexpr

Cranking enrichment values range from 0% to 1275%.

IGNITION_ADVANCE_LARGE

constexpr conversionFactor<int8_t, uint8_t> IGNITION_ADVANCE_LARGE = { .scale=1U, .translate=-40 }

staticconstexpr

Ignition values from the main spark table are offset 40 degrees downwards to allow for negative spark timing.

IGNITION_ADVANCE_SMALL

constexpr conversionFactor<int8_t, uint8_t> IGNITION_ADVANCE_SMALL = { .scale=1U, .translate=-15 }

staticconstexpr

Ignition advance adjustments can use a smaller offset.

MAP

constexpr conversionFactor<uint16_t, uint8_t> MAP = { .scale=2U, .translate=0U }

staticconstexpr

MAP values: kpa.

MAP_DOT

constexpr conversionFactor<int16_t, uint8_t> MAP_DOT = { .scale=10U, .translate=0U }

staticconstexpr

MAP rate of change: kpa/s

RPM_COARSE

constexpr conversionFactor<uint16_t, uint8_t> RPM_COARSE = { .scale=100U, .translate=0U }

staticconstexpr

RPM stored as RPM/100. E.g. 2700 -> 27 -> 2700.

RPM_FINE

constexpr conversionFactor<uint16_t, uint8_t> RPM_FINE = { .scale=5U, .translate=0U }

staticconstexpr

RPM stored as RPM/5. E.g. 1300->260->1300.

This limits the maximum value to 1275 RPM, but gives more precision than RPM_MEDIUM

RPM_MEDIUM

constexpr conversionFactor<uint16_t, uint8_t> RPM_MEDIUM = { .scale=10U, .translate=0U }

staticconstexpr

RPM stored as RPM/10. E.g. 2700 -> 270 -> 2700.

This limits the maximum value to 2550 RPM, but gives more precision than RPM_COARSE

TEMPERATURE

constexpr conversionFactor<int16_t, uint8_t> TEMPERATURE = { .scale=1U, .translate=-40 }

staticconstexpr

All temperature measurements are stored offset by 40 degrees, to represent temperature ranges from -40 to 215.

TIME_TEN_MILLIS

constexpr conversionFactor<uint16_t, uint8_t> TIME_TEN_MILLIS = { .scale=100U, .translate=0U }

staticconstexpr

Time values stored in 10 milliseconds.

We convert to/from µS

TIME_TENTH_MILLIS

constexpr conversionFactor<uint32_t, uint8_t> TIME_TENTH_MILLIS = { .scale=10000U, .translate=0U }

staticconstexpr

Time values stored in 1/10th milliseconds I.e ms/10.

We convert to/from µS

TIME_TWENTY_MILLIS

constexpr conversionFactor<uint16_t, uint8_t> TIME_TWENTY_MILLIS = { .scale=5U, .translate=0U }

staticconstexpr

Time values stored in 20 milliseconds.

We convert to/from secs/0.1

TPS_DOT

constexpr conversionFactor<int16_t, uint8_t> TPS_DOT = { .scale=10U, .translate=0U }

staticconstexpr

TPS rate of change: %/s.