wayne roberts / TimeoutAbs

Timeout driver for event at absolute time

Dependents:   demo_TimeoutAbs i2c_lora_slave

Timeout driver for generating event at absolute time, i.e. alarm at 12:00PM instead of alarm in 5 minutes.

This is the same concept as TIMER_ABSTIME in clock_nanosleep().

The purpose is to remove dependency on when attach() is called, so the event occurs at correct time regardless of any latency in calling attach().

This driver doesnt add any functionality over mbed-os library; it only skips the call to ticker_read_us() in Ticker::setup(), which just changes a relative time to absolute time.

example use here.

TimeoutAbs.h

Committer:
Wayne Roberts
Date:
2018-12-07
Revision:
1:ae6b29794806
Parent:
0:900163d530ae

File content as of revision 1:ae6b29794806:

#ifndef _TOABS_H_
#define _TOABS_H_
#include "drivers/TimerEvent.h"
#include "platform/Callback.h"
#include "platform/mbed_toolchain.h"
#include "platform/NonCopyable.h"
#include "platform/mbed_power_mgmt.h"
#include "hal/lp_ticker_api.h"
#include "platform/mbed_critical.h" 

namespace mbed {

class TimeoutAbs : public TimerEvent, private NonCopyable<TimeoutAbs> {
    public:
        TimeoutAbs() : TimerEvent(), _function(0), _lock_deepsleep(true)
        {
        }

        TimeoutAbs(const ticker_data_t* data) : TimerEvent(data), _function(0), _lock_deepsleep(true)
        {
#if DEVICE_LPTICKER
        _lock_deepsleep = (data != get_lp_ticker_data());
#endif 
        }

        virtual ~TimeoutAbs()
        {
            detach();
        }

        /** Detach the function
         */
        void detach();

    void attach_us(Callback<void()> func, us_timestamp_t t)
    {
        core_util_critical_section_enter();
        // lock only for the initial callback setup and this is not low power ticker
        if (!_function && _lock_deepsleep) {
            sleep_manager_lock_deep_sleep();
        }
        _function = func;
        abs_setup(t);
        core_util_critical_section_exit();
    }

	us_timestamp_t read_us(void)
	{
		return ticker_read_us(_ticker_data);
	}

    protected:
		void abs_setup(us_timestamp_t);
        virtual void handler();
        Callback<void()>    _function;  /**< Callback. */
        bool          _lock_deepsleep;  /**< Flag which indicates if deep sleep should be disabled. */
};

} // namespace mbed
#endif /* _TOABS_H_ */