Deals with busy delays, elapsed time and accumulated time. More...

#include <longan_nano_chrono.hpp>

Public Types
enum	_Config { PEDANTIC_CHECKS = false, SYSTICK_INVALID = 0xFFFFFFFF, SYSTICK_PRE = 4, TIME_INVALID = -1 }
	Configurations of the SysTick. More...

enum	_Unit { milliseconds, microseconds }
	Possible time units. Same names as std::Chrono. More...

typedef enum Longan_nano::Chrono::_Config	Config
	Configurations of the SysTick. More...

typedef enum Longan_nano::Chrono::_Unit	Unit
	Possible time units. Same names as std::Chrono. More...

Public Member Functions
	Chrono (void)
	Empty Constructor Chrono \| void. More...

	~Chrono (void)
	Empty Destructor. More...

void	start (void)
	public method start \| void More...

void	restart (void)
	public method start \| void More...

void	stop (void)
	public method stop \| void More...

int32_t	stop (Unit unit)
	public method stop \| Unit \| More...

bool	accumulate (void)
	public method accumulate \| void \| More...

int32_t	accumulate (Unit unit)
	public method accumulate \| Unit unit \| More...

int32_t	get_elapsed (Unit unit)
	public getter get_elapsed \| Unit \| More...

int32_t	get_accumulator (Unit unit)
	public getter get_accumulator \| Unit \| More...

Static Public Member Functions
static unsigned int	get_systick_freq (void)
	public static method get_systick_freq \| void More...

static bool	delay (Unit unit, unsigned int delay_tmp)
	public static method delay \| Unit \| unsigned int \| More...

Private Member Functions
int32_t	compute_elapsed (uint64_t start, uint64_t stop, Unit unit)
	private method compute_elapsed \| uint64_t \| uint64_t \| Unit \| More...

int32_t	compute_accumulator (uint64_t accumulator, Unit unit)
	private method compute_accumulator \| uint64_t \| Unit \| More...

Static Private Member Functions
static uint32_t	compute_tick_per_time_unit (Unit unit)
	private method compute_tick_per_time_unit \| Unit \| More...

Private Attributes
bool	g_f_accumulator_mode

uint64_t	g_systick_start

uint64_t	g_systick_stop

Detailed Description

Deals with busy delays, elapsed time and accumulated time.

Author: Orso Eric

Version: 2020-08-08

Bug:: None

Copyright: BSD 3-Clause License Copyright (c) 2020, Orso Eric

SysTick
Use 64b 27MHz SysTick timer.
History Version
2020-07-20
Rework Utils library into Chrono library to add start/stop timer
"start" snaps the start timestamp at full resolution
"stop" snaps the stop timestamp at full resolution
"elapsed" returns the elapsed time between stop and start if valid. zero otherwise
2020-07-28
I need a method to accumulate execution time and profile how long an activity has taken
"accumulate" add stop-start to an internal accumulator at full resolution
Add combined "stop" "elapsed" implementation with better performance and fewer calls needed
I can combine the stop and accumulator counters since i use one or the other
I use a flag to handle initialization and invalid when switching between modes and automatically reset the accumulator
2020-08-04
Refactor to separate header and implementation

Member Typedef Documentation

◆ Config

typedef enum Longan_nano::Chrono::_Config Longan_nano::Chrono::Config

Configurations of the SysTick.

◆ Unit

typedef enum Longan_nano::Chrono::_Unit Longan_nano::Chrono::Unit

Possible time units. Same names as std::Chrono.

Member Enumeration Documentation

◆ _Config

enum Longan_nano::Chrono::_Config

Configurations of the SysTick.

Enumerator
PEDANTIC_CHECKS
SYSTICK_INVALID
SYSTICK_PRE
TIME_INVALID

◆ _Unit

enum Longan_nano::Chrono::_Unit

Possible time units. Same names as std::Chrono.

Enumerator
milliseconds
microseconds

Constructor & Destructor Documentation

◆ Chrono()

Longan_nano::Chrono::Chrono ( void )

Empty Constructor Chrono | void.

Returns: void

Initialize timestamps to invalid

◆ ~Chrono()

Longan_nano::Chrono::~Chrono ( void )

Empty Destructor.

~Chrono | void

Returns: void

Member Function Documentation

◆ accumulate() [1/2]

int32_t Longan_nano::Chrono::accumulate ( Unit unit )

public method accumulate | Unit unit |

Parameters

unit	\| Unit \| result is given in this time unit

Returns: unsigned int | frequency of the SysTick timer

Snap the stop time
Accumulate the difference between stop and start inside the accumulator
Swap the stop and start, invalidate the stop. Prepare for next cycle

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◆ accumulate() [2/2]

bool Longan_nano::Chrono::accumulate ( void )

public method accumulate | void |

Returns: unsigned int | frequency of the SysTick timer

Snap the stop time
Accumulate the difference between stop and start inside the accumulator
Swap the stop and start, invalidate the stop. Prepare for next cycle
Use stop counter as accumulator
If timer was in timer mode, reset the accumulator

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◆ compute_accumulator()

int32_t Longan_nano::Chrono::compute_accumulator	(	uint64_t	accumulator,
		Unit	unit
	)

private

private method compute_accumulator | uint64_t | Unit |

Parameters

accumulator	\| uint64_t \| timestamp DeltaT
unit	\| Unit \| result is given in this time unit

Returns: int32_t | negative = invalid | zero or positive = elapsed time in the given time unit

use start and stop timestamp to compute the elapsed time in a given time unit

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◆ compute_elapsed()

int32_t Longan_nano::Chrono::compute_elapsed	(	uint64_t	start,
		uint64_t	stop,
		Unit	unit
	)

inlineprivate

private method compute_elapsed | uint64_t | uint64_t | Unit |

Parameters

start	\| uint64_t \| timestamp
stop	\| uint64_t \| timestamp
unit	\| Unit \| result is given in this time unit

Returns: int32_t | negative = invalid | zero or positive = elapsed time in the given time unit

use start and stop timestamp to compute the elapsed time in a given time unit

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◆ compute_tick_per_time_unit()

uint32_t Longan_nano::Chrono::compute_tick_per_time_unit ( Unit unit )

inlinestaticprivate

private method compute_tick_per_time_unit | Unit |

Parameters

unit	\| Unit \| result is given in this time unit

Returns: uint32_t | number of systick counts needed to count one time unit

Compute the number of systick counts needed to count one time unit

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◆ delay()

bool Longan_nano::Chrono::delay	(	Unit	unit,
		unsigned int	delay_tmp
	)

static

public static method delay | Unit | unsigned int |

Parameters

unit	\| Unit \| timeunit of the delay
delay_tmp	\| unsigned int \| how long to wait for

Returns: bool | false = OK | true = fail

Use the SysTick timer counter to busy wait for the correct number of microseconds
The CPU SysTick timer is clocked by the ABH clock/4 = 27MHz
SystemCoreClock defines the frequency of the CPU in Hz

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◆ get_accumulator()

int32_t Longan_nano::Chrono::get_accumulator ( Unit unit )

inline

public getter get_accumulator | Unit |

Parameters

unit	\| Unit \| result is given in this time unit

Returns: int | accumulators. negative mean the timer was uninitialized

return the DeltaT accumulated by the accumulate function in the given time unit

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◆ get_elapsed()

int32_t Longan_nano::Chrono::get_elapsed ( Unit unit )

public getter get_elapsed | Unit |

Parameters

unit	\| Unit \| result is given in this time unit

Returns: int | elapsed time. negative mean the timer was uninitialized

Time elapsed between start and stop

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◆ get_systick_freq()

unsigned int Longan_nano::Chrono::get_systick_freq ( void )

static

public static method get_systick_freq | void

Returns: unsigned int | frequency of the SysTick timer

The SysTick timer is tied to the CPU clock prescaled by four

◆ restart()

void Longan_nano::Chrono::restart ( void )

public method start | void

Returns: void

Start the timer and invalidate the stop time and accumulator

◆ start()

void Longan_nano::Chrono::start ( void )

public method start | void

Returns: void

Start the timer

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◆ stop() [1/2]

int32_t Longan_nano::Chrono::stop ( Unit unit )

public method stop | Unit |

Parameters

unit	\| Unit \| result is given in this time unit

Returns: void

Stop the timer. Snap the stop time
Return the elapsed time between stop and start in the given unit

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◆ stop() [2/2]

void Longan_nano::Chrono::stop ( void )

public method stop | void

Returns: void

Stop the timer. Snap the stop time

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Member Data Documentation

◆ g_f_accumulator_mode

bool Longan_nano::Chrono::g_f_accumulator_mode

private

◆ g_systick_start

uint64_t Longan_nano::Chrono::g_systick_start

private

◆ g_systick_stop

uint64_t Longan_nano::Chrono::g_systick_stop

private

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

src/longan_nano_chrono.hpp

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ Config

◆ Unit

Member Enumeration Documentation

◆ _Config

◆ _Unit

Constructor & Destructor Documentation

◆ Chrono()

◆ ~Chrono()

Member Function Documentation

◆ accumulate() [1/2]

◆ accumulate() [2/2]

◆ compute_accumulator()

◆ compute_elapsed()

◆ compute_tick_per_time_unit()

◆ delay()

◆ get_accumulator()

◆ get_elapsed()

◆ get_systick_freq()

◆ restart()

◆ start()

◆ stop() [1/2]

◆ stop() [2/2]

Member Data Documentation

◆ g_f_accumulator_mode

◆ g_systick_start

◆ g_systick_stop