crankMaths.h File Reference

Crank revolution based mathematical functions. More...

#include "maths.h"
#include "globals.h"

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Functions
static int16_t	ignitionLimits (int16_t angle)
	Makes one pass at nudging the angle to within [0,CRANK_ANGLE_MAX_IGN].
static int16_t	injectorLimits (int16_t angle)
	Makes one pass at nudging the angle to within [0,CRANK_ANGLE_MAX_INJ].
void	setAngleConverterRevolutionTime (uint32_t revolutionTime)
	Set the revolution time, from which some of the degree<-->angle conversions are derived.
uint32_t	angleToTimeMicroSecPerDegree (uint16_t angle)
	Converts angular degrees to the time interval that amount of rotation will take at current RPM.
COMPARE_TYPE	angleToTimerTicks (uint16_t angle)
	Converts angular degrees to the equivalent timer ticks at current RPM.
uint16_t	timeToAngleDegPerMicroSec (uint32_t time)
	Converts a time interval in microsecods to the equivalent degrees of angular (crank) rotation at current RPM.

Variables
static constexpr uint32_t	MICROS_PER_DEG_1_RPM = UDIV_ROUND_CLOSEST(MICROS_PER_MIN, 360UL, uint32_t)
	At 1 RPM, each degree of angular rotation takes this many microseconds.
static constexpr uint16_t	MAX_RPM = 18000U
	The maximum rpm that the ECU will attempt to run at.
static constexpr uint16_t	MIN_RPM = (uint16_t)UDIV_ROUND_UP(MICROS_PER_DEG_1_RPM, (uint32_t)UINT16_MAX/16UL, uint32_t)
	Absolute minimum RPM that the crank math (& therefore all of Speeduino) can be used with.
static constexpr uint16_t	MIN_REVOLUTION_TIME = MICROS_PER_MIN/MAX_RPM
	Minimum time in µS that one crank revolution can take.
static constexpr uint32_t	MAX_REVOLUTION_TIME = MICROS_PER_MIN/MIN_RPM
	Maximum time in µS that one crank revolution can take.

Detailed Description

Crank revolution based mathematical functions.

Function Documentation

angleToTimeMicroSecPerDegree()

uint32_t angleToTimeMicroSecPerDegree

(

uint16_t

angle

)

Converts angular degrees to the time interval that amount of rotation will take at current RPM.

Based on angle of [0,720] and min/max RPM, result ranges from 9 (MAX_RPM, 1 deg) to 2926828 (MIN_RPM, 720 deg)

Parameters

angle

Angle in degrees

Returns

Time interval in uS

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angleToTimerTicks()

COMPARE_TYPE angleToTimerTicks

(

uint16_t

angle

)

Converts angular degrees to the equivalent timer ticks at current RPM.

Parameters

angle

Angle in degrees

Returns

Number of timer ticks

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ignitionLimits()

static int16_t ignitionLimits ( int16_t  angle )

inlinestatic

Makes one pass at nudging the angle to within [0,CRANK_ANGLE_MAX_IGN].

Parameters

angle

A crank angle in degrees

Returns

int16_t

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injectorLimits()

static int16_t injectorLimits ( int16_t  angle )

inlinestatic

Makes one pass at nudging the angle to within [0,CRANK_ANGLE_MAX_INJ].

Parameters

angle

A crank angle in degrees

Returns

int16_t

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setAngleConverterRevolutionTime()

void setAngleConverterRevolutionTime

(

uint32_t

revolutionTime

)

Set the revolution time, from which some of the degree<-->angle conversions are derived.

Parameters

revolutionTime

The crank revolution time.

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timeToAngleDegPerMicroSec()

uint16_t timeToAngleDegPerMicroSec

(

uint32_t

time

)

Converts a time interval in microsecods to the equivalent degrees of angular (crank) rotation at current RPM.

Inverse of angleToTimeMicroSecPerDegree

Parameters

time	Time interval in uS

Returns

Angle in degrees

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Variable Documentation

MAX_REVOLUTION_TIME

constexpr uint32_t MAX_REVOLUTION_TIME = MICROS_PER_MIN/MIN_RPM

staticconstexpr

Maximum time in µS that one crank revolution can take.

Note

: many calculations are done over 2 revolutions (cycles), in which case this would be doubled

MAX_RPM

constexpr uint16_t MAX_RPM = 18000U

staticconstexpr

The maximum rpm that the ECU will attempt to run at.

It is NOT related to the rev limiter, but is instead dictates how fast certain operations will be allowed to run. Lower number gives better performance

MICROS_PER_DEG_1_RPM

constexpr uint32_t MICROS_PER_DEG_1_RPM = UDIV_ROUND_CLOSEST(MICROS_PER_MIN, 360UL, uint32_t)

staticconstexpr

At 1 RPM, each degree of angular rotation takes this many microseconds.

MIN_REVOLUTION_TIME

constexpr uint16_t MIN_REVOLUTION_TIME = MICROS_PER_MIN/MAX_RPM

staticconstexpr

Minimum time in µS that one crank revolution can take.

Note

: many calculations are done over 2 revolutions (cycles), in which case this would be doubled

MIN_RPM

constexpr uint16_t MIN_RPM = (uint16_t)UDIV_ROUND_UP(MICROS_PER_DEG_1_RPM, (uint32_t)UINT16_MAX/16UL, uint32_t)

staticconstexpr

Absolute minimum RPM that the crank math (& therefore all of Speeduino) can be used with.

This is dictated by the use of uint16_t as the base type for storing time --> angle conversion factor (degreesPerMicro)