os::rtos::clock_systick Class Reference

SysTick derived clock. More...

#include <cmsis-plus/rtos/os.h>

Inheritance diagram for os::rtos::clock_systick:

Public Types
Types & Constants
using	duration_t = port::clock::duration_t
	Type of variables holding clock durations.
using	timestamp_t = port::clock::timestamp_t
	Type of variables holding clock time stamps.
using	offset_t = port::clock::offset_t
	Type of variables holding clock offsets.

Public Member Functions
Constructors & Destructor
	clock_systick ()
	Construct a SysTick clock object instance.
virtual	~clock_systick () override
	Destruct the SysTick clock object instance.
Public Member Functions
virtual timestamp_t	now (void)
	Tell the current time, possibly adjusted for epoch.
timestamp_t	steady_now (void)
	Tell the current time since startup.
result_t	sleep_for (duration_t duration)
	Sleep for a relative duration.
virtual result_t	sleep_until (timestamp_t timestamp)
	Sleep until an absolute timestamp.
result_t	wait_for (duration_t timeout)
	Timed wait for an event.
timestamp_t	update_for_slept_time (duration_t duration)
	Increase the internal count after a deep sleep.
virtual offset_t	offset (void)
	Get adjustment offset (placeholder).
virtual offset_t	offset (offset_t value)
	Set adjustment offset (placeholder)
Public Member Functions
const char *	name (void) const
	Get object name.

Static Public Attributes
Types & Constants
static constexpr uint32_t	frequency_hz = OS_INTEGER_SYSTICK_FREQUENCY_HZ
	SysTick frequency in Hz.

Public Member Functions
virtual void	start (void) override
	Start the clock.
template<typename Rep_T >
static constexpr clock::duration_t	ticks_cast (Rep_T microsec)
	Convert microseconds to ticks.

Detailed Description

Definition at line 460 of file os-clocks.h.

Constructor & Destructor Documentation

clock_systick()

os::rtos::clock_systick::clock_systick

(

)

~clock_systick()

virtual os::rtos::clock_systick::~clock_systick ( )

overridevirtual

Member Function Documentation

name()

const char * os::rtos::internal::object_named::name ( void  ) const

inlineinherited

Parameters

None.

Returns

A null terminated string.

All objects return a non-null string; anonymous objects return "-".

Note

Can be invoked from Interrupt Service Routines.

Definition at line 753 of file os-decls.h.

      {
        return name_;
      }

Referenced by os::memory::lifo::lifo(), os::memory::malloc_memory_resource::malloc_memory_resource(), os::rtos::message_queue_typed< T, Allocator >::message_queue_typed(), os::memory::block_pool::~block_pool(), os::rtos::event_flags::~event_flags(), os::memory::first_fit_top::~first_fit_top(), os::memory::lifo::~lifo(), os::memory::malloc_memory_resource::~malloc_memory_resource(), os::rtos::memory_pool::~memory_pool(), os::rtos::message_queue::~message_queue(), os::rtos::mutex::~mutex(), os::rtos::semaphore::~semaphore(), os::rtos::thread::~thread(), os::rtos::timer::~timer(), os::rtos::memory_pool::alloc(), os::rtos::thread::cancel(), os::rtos::event_flags::clear(), os::rtos::mutex::consistent(), os::rtos::thread::detach(), os::memory::new_delete_memory_resource::do_allocate(), os::memory::block_pool::do_allocate(), os::memory::first_fit_top::do_allocate(), os::memory::lifo::do_allocate(), os::memory::malloc_memory_resource::do_allocate(), os::rtos::thread::flags_raise(), os::rtos::memory_pool::free(), os::rtos::event_flags::get(), os::rtos::thread::interrupt(), os::rtos::thread::join(), os::rtos::thread::kill(), os::rtos::internal::terminated_threads_list::link(), os::rtos::mutex::lock(), os::rtos::memory::memory_resource::out_of_memory_handler(), os::rtos::semaphore::post(), os::rtos::mutex::prio_ceiling(), os::rtos::mutex::prio_ceiling(), os::rtos::thread::priority(), os::rtos::thread::priority_inherited(), os::rtos::event_flags::raise(), os::rtos::message_queue::receive(), os::rtos::memory_pool::reset(), os::rtos::message_queue::reset(), os::rtos::mutex::reset(), os::rtos::semaphore::reset(), os::rtos::thread::resume(), os::rtos::message_queue::send(), os::rtos::clock::sleep_for(), os::rtos::timer::start(), os::rtos::timer::stop(), os::rtos::memory_pool::timed_alloc(), os::rtos::mutex::timed_lock(), os::rtos::message_queue::timed_receive(), os::rtos::message_queue::timed_send(), os::rtos::semaphore::timed_wait(), os::rtos::event_flags::timed_wait(), os::rtos::memory::memory_resource::trace_print_statistics(), os::rtos::memory_pool::try_alloc(), os::rtos::mutex::try_lock(), os::rtos::message_queue::try_receive(), os::rtos::message_queue::try_send(), os::rtos::event_flags::try_wait(), os::rtos::semaphore::try_wait(), os::rtos::internal::ready_threads_list::unlink_head(), os::rtos::mutex::unlock(), os::rtos::event_flags::wait(), os::rtos::semaphore::wait(), and os::rtos::event_flags::waiting().

now()

clock::timestamp_t os::rtos::clock::now ( void  )

virtualinherited

Parameters

None.

Returns

The clock current timestamp (time units from startup plus the epoch offset).

Note

Can be invoked from Interrupt Service Routines.

Reimplemented in os::rtos::adjustable_clock, and os::rtos::clock_highres.

Definition at line 147 of file os-clocks.cpp.

    {
      // ----- Enter critical section -----------------------------------------
      interrupts::critical_section ics;
 
      // Prevent inconsistent values using the critical section.
      return steady_count_;
      // ----- Exit critical section ------------------------------------------
    }

Referenced by os::rtos::internal::clock_timestamps_list::check_timestamp(), os::estd::chrono::systick_clock::now(), os::estd::chrono::system_clock::now(), os_sysclock_now(), and os::rtos::clock::sleep_until().

offset() [1/2]

virtual offset_t os::rtos::clock::offset ( offset_t  value )

virtualinherited

Parameters

[in]

value

Ignored for steady clocks.

Returns

0 for steady clocks.

Reimplemented in os::rtos::adjustable_clock.

offset() [2/2]

clock::offset_t os::rtos::clock::offset ( void  )

virtualinherited

Parameters

None.

Returns

0 for steady clocks.

Reimplemented in os::rtos::adjustable_clock.

Definition at line 335 of file os-clocks.cpp.

    {
      return 0;
    }

sleep_for()

result_t os::rtos::clock::sleep_for ( duration_t  duration )

inherited

Parameters

[in]

duration

The number of clock units (ticks or seconds) to sleep.

Return values

ETIMEDOUT	The sleep lasted the entire duration.
EPERM	Cannot be invoked from an Interrupt Service Routines.
EINTR	The sleep was interrupted.

Warning

Cannot be invoked from Interrupt Service Routines.

Definition at line 175 of file os-clocks.cpp.

    {
#if defined(OS_TRACE_RTOS_CLOCKS)
 
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
      trace::printf ("%s(%u) %p %s\n", __func__,
                     static_cast<unsigned int> (duration),
                     &this_thread::thread (), this_thread::thread ().name ());
#pragma GCC diagnostic pop
 
#endif // defined(OS_TRACE_RTOS_CLOCKS)
 
      // Don't call this from interrupt handlers.
      os_assert_err (!interrupts::in_handler_mode (), EPERM);
      // Don't call this from critical regions.
      os_assert_err (!scheduler::locked (), EPERM);
 
      clock::timestamp_t timestamp = steady_now () + duration;
      for (;;)
        {
          result_t res;
          res = internal_wait_until_ (timestamp, steady_list_);
 
          timestamp_t n = steady_now ();
          if (n >= timestamp)
            {
              return ETIMEDOUT;
            }
 
          if (this_thread::thread ().interrupted ())
            {
              return EINTR;
            }
 
          if (res != result::ok)
            {
              return res;
            }
        }
      return ENOTRECOVERABLE;
    }

References os::rtos::interrupts::in_handler_mode(), os::rtos::scheduler::locked(), os::rtos::internal::object_named::name(), os::rtos::result::ok, os_assert_err, os::trace::printf(), os::rtos::clock::steady_now(), and os::rtos::this_thread::thread().

Referenced by os_sysclock_sleep_for(), and osDelay().

sleep_until()

result_t os::rtos::clock::sleep_until ( timestamp_t  timestamp )

virtualinherited

Parameters

[in]

timestamp

The absolute moment in time, in clock units.

Return values

ETIMEDOUT	The sleep lasted the entire duration.
EPERM	Cannot be invoked from an Interrupt Service Routines.
EINTR	The sleep was interrupted.

Warning

Cannot be invoked from Interrupt Service Routines.

Reimplemented in os::rtos::adjustable_clock.

Definition at line 225 of file os-clocks.cpp.

    {
#if defined(OS_TRACE_RTOS_CLOCKS)
      trace::printf ("%s()\n", __func__);
#endif
 
      // Don't call this from interrupt handlers.
      os_assert_err (!interrupts::in_handler_mode (), EPERM);
      // Don't call this from critical regions.
      os_assert_err (!scheduler::locked (), EPERM);
 
      for (;;)
        {
          result_t res;
          res = internal_wait_until_ (timestamp, steady_list_);
 
          timestamp_t nw = now ();
          if (nw >= timestamp)
            {
              return ETIMEDOUT;
            }
 
          if (this_thread::thread ().interrupted ())
            {
              return EINTR;
            }
 
          if (res != result::ok)
            {
              return res;
            }
        }
      return ENOTRECOVERABLE;
    }

References os::rtos::interrupts::in_handler_mode(), os::rtos::scheduler::locked(), os::rtos::clock::now(), os::rtos::result::ok, os_assert_err, os::trace::printf(), and os::rtos::this_thread::thread().

Referenced by os_sysclock_sleep_until().

start()

virtual void os::rtos::clock_systick::start ( void  )

overridevirtual

Parameters

None.

Returns

Nothing.

For system clocks it is called from the system startup code.

Implements os::rtos::clock.

Referenced by os::rtos::scheduler::start().

steady_now()

clock::timestamp_t os::rtos::clock::steady_now ( void  )

inherited

Parameters

None.

Returns

The clock current steady timestamp (time units from startup).

Note

Can be invoked from Interrupt Service Routines.

Definition at line 161 of file os-clocks.cpp.

    {
      // ----- Enter critical section -----------------------------------------
      interrupts::critical_section ics;
 
      // Prevent inconsistent values using the critical section.
      return steady_count_;
      // ----- Exit critical section ------------------------------------------
    }

Referenced by os::rtos::clock::sleep_for(), and os::rtos::clock::wait_for().

ticks_cast()

template<typename Rep_T >

static constexpr clock::duration_t os::rtos::clock_systick::ticks_cast ( Rep_T  microsec )

staticconstexpr

Template Parameters

Rep_T

Type of input, auto deduced (usually uint32_t or uin64_t)

Parameters

[in]

microsec

The number of microseconds.

Returns

The number of ticks.

Referenced by osDelay(), osMutexWait(), osSignalWait(), and osTimerStart().

update_for_slept_time()

clock::timestamp_t os::rtos::clock::update_for_slept_time ( duration_t  duration )

inherited

Parameters

duration

Number of ticks lost during sleep.

Returns

The clock current steady timestamp (time units from startup).

During deep sleep the interrupts used to count clock ticks are usually disabled and an external RTC is configured to wake-up the device, so a number of clock ticks are lost.

To keep the clocks accurate, it is recommended to sample the external RTC before entering deep sleep and again when the device is back to life, compute the time slept as difference, and use this function to update the internal clock counter.

Definition at line 315 of file os-clocks.cpp.

    {
      // ----- Enter critical section -----------------------------------------
      interrupts::critical_section ics;
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wdeprecated-volatile"
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wvolatile"
#endif
      steady_count_ += duration;
#pragma GCC diagnostic pop
 
      internal_check_timestamps ();
      return steady_count_;
      // ----- Exit critical section ------------------------------------------
    }

wait_for()

result_t os::rtos::clock::wait_for ( duration_t  timeout )

inherited

Parameters

[in]

timeout

The timeout in clock units.

Return values

result::ok	An event occurred before the timeout.
ETIMEDOUT	The wait lasted the entire duration.
EPERM	Cannot be invoked from an Interrupt Service Routines.
EINTR	The sleep was interrupted.

Warning

Cannot be invoked from Interrupt Service Routines.

Definition at line 264 of file os-clocks.cpp.

    {
#if defined(OS_TRACE_RTOS_CLOCKS)
 
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
      trace::printf ("%s(%u)\n", __func__,
                     static_cast<unsigned int> (timeout));
#pragma GCC diagnostic pop
 
#endif // defined(OS_TRACE_RTOS_CLOCKS)
 
      // Don't call this from interrupt handlers.
      os_assert_err (!interrupts::in_handler_mode (), EPERM);
      // Don't call this from critical regions.
      os_assert_err (!scheduler::locked (), EPERM);
 
      clock::timestamp_t timestamp = steady_now () + timeout;
 
      result_t res;
      res = internal_wait_until_ (timestamp, steady_list_);
 
      timestamp_t nw = steady_now ();
      if (nw >= timestamp)
        {
          return ETIMEDOUT;
        }
 
      if (this_thread::thread ().interrupted ())
        {
          return EINTR;
        }
 
      return res;
    }

References os::rtos::interrupts::in_handler_mode(), os::rtos::scheduler::locked(), os_assert_err, os::trace::printf(), os::rtos::clock::steady_now(), and os::rtos::this_thread::thread().

Referenced by os_sysclock_wait_for().

Member Data Documentation

frequency_hz

constexpr uint32_t os::rtos::clock_systick::frequency_hz = OS_INTEGER_SYSTICK_FREQUENCY_HZ

staticconstexpr

Definition at line 471 of file os-clocks.h.

Referenced by main(), and os_systick_handler().

---

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

• os-clocks.h