TickerDataClock Class Reference

A partial implementation of a C++11 Clock representing a HAL ticker. More...

#include <TickerDataClock.h>

Public Member Functions
constexpr	TickerDataClock (const ticker_data_t *ticker)
	Construct a TickerDataClock referring to a ticker_data_t. More...
void	set_handler (ticker_event_handler handler)
	Initialize a ticker and set the event handler. More...
void	remove_event (ticker_event_t *obj)
	Remove an event from the queue. More...
void	insert_event (ticker_event_t *obj, time_point timestamp, uint32_t id)
	Insert an event to the queue. More...
time_point	now () const
	Read the current (absolute) ticker's timestamp. More...
int	get_next_timestamp (time_point *timestamp) const
	Read the next event's timestamp. More...
void	suspend ()
	Suspend this ticker. More...
void	resume ()
	Resume this ticker. More...

Detailed Description

A partial implementation of a C++11 Clock representing a HAL ticker.

This class allows us to create chrono time_points for objects like Timer, with the limitation that the tickers are not singletons. This means:

• the now() function is not static - this will limit use with some algorithms,
• there is no distinction between time_points for different tickers

This "pseudo-Clock" approach has been endorsed by Howard Hinnant (designer of Chrono) here: https://stackoverflow.com/questions/56400313/why-does-the-c-standard-require-the-clocknow-function-to-be-static

TickerDataClock::time_point values should only be used with mbed APIs specifically taking them, not passed to generic templated chrono algorithms, and it is up to the user to use them in conjunction with the correct TickerDataClock.

operators for -> and conversion to ticker_data_t * are provided allowing TickerDataClock to be easily substituted in place of a ticker_data_t *.

Definition at line 52 of file TickerDataClock.h.

Constructor & Destructor Documentation

TickerDataClock()

constexpr TickerDataClock ( const ticker_data_t *  ticker )

constexpr

Construct a TickerDataClock referring to a ticker_data_t.

Definition at line 55 of file TickerDataClock.h.

Member Function Documentation

set_handler()

void set_handler

(

ticker_event_handler

handler

)

Initialize a ticker and set the event handler.

Parameters

handler

A handler to be set

Definition at line 70 of file TickerDataClock.h.

remove_event()

void remove_event

(

ticker_event_t *

obj

)

Remove an event from the queue.

Parameters

obj	The event object to be removed from the queue

Definition at line 79 of file TickerDataClock.h.

insert_event()

void insert_event	(	ticker_event_t *	obj,
		time_point	timestamp,
		uint32_t	id
	)

Insert an event to the queue.

The event will be executed in timestamp - ticker_read_us() us.

Note

If an event is inserted with a timestamp less than the current timestamp then the event will be scheduled immediately resulting in an instant call to event handler.

Parameters

obj	The event object to be inserted to the queue
timestamp	The event's timestamp
id	The event object

Definition at line 96 of file TickerDataClock.h.

now()

time_point now

(

)

const

Read the current (absolute) ticker's timestamp.

Warning

Return an absolute timestamp counting from the initialization of the ticker.

Returns

The current timestamp

Definition at line 108 of file TickerDataClock.h.

get_next_timestamp()

int get_next_timestamp

(

time_point *

timestamp

)

const

Read the next event's timestamp.

Parameters

timestamp

The timestamp object.

Returns

1 if timestamp is pending event, 0 if there's no event pending

Definition at line 118 of file TickerDataClock.h.

suspend()

void suspend

(

)

Suspend this ticker.

When suspended reads will always return the same time and no events will be dispatched. When suspended the common layer will only ever call the interface function clear_interrupt() and that is only if ticker_irq_handler is called.

Definition at line 134 of file TickerDataClock.h.

resume()

void resume

(

)

Resume this ticker.

When resumed the ticker will ignore any time that has passed and continue counting up where it left off.

Definition at line 144 of file TickerDataClock.h.