43 lines
2.3 KiB
ReStructuredText
43 lines
2.3 KiB
ReStructuredText
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.. _nanokernel_timers:
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Timer Services
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##############
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Definition
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**********
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The timer objects is defined in :file:`kernel/nanokernel/nano_timer.c`
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and implements digital counters that either increment or decrement at a
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fixed frequency. Timers can be called from a task or fiber context.
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Function
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********
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Only a fiber or task context can call timers. Timers can only be used in
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a nanokernel if it is not part of a microkernel. Timers are optional in
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nanokernel-only systems. The nanokernel timers are simple. The
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:c:func:`nano_node_tick_delta()` routine is not reentrant and should
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only be called from a single context, unless it is certain other
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contexts are not using the elapsed timer.
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APIs
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****
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+--------------------------------+----------------------------------------------------------------+
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| Context | Interface |
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+================================+================================================================+
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| **Initialization** | :c:func:`nano_timer_init()` |
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+--------------------------------+----------------------------------------------------------------+
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| **Interrupt Service Routines** | |
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+--------------------------------+----------------------------------------------------------------+
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| **Fibers** | :c:func:`nano_fiber_timer_test()`, |
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| | :c:func:`nano_fiber_timer_wait()`, |
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| | :c:func:`nano_fiber_timer_start()`, |
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| | :c:func:`nano_fiber_timer_stop()` |
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+--------------------------------+----------------------------------------------------------------+
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| **Tasks** | :c:func:`nano_task_timer_test()`, |
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| | :c:func:`nano_task_timer_wait()`, |
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| | :c:func:`nano_task_timer_start()`, |
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| | :c:func:`nano_task_timer_stop()` |
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+--------------------------------+----------------------------------------------------------------+
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