EL4121 Embedded System / mbed-os

mbed-os

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events/mbed_shared_queues.h@0:b74591d5ab33, 2017-12-11 (annotated)

Committer:
be_bryan
Date:
Mon Dec 11 17:54:04 2017 +0000
Revision:
0:b74591d5ab33
motor ++

Who changed what in which revision?

UserRevisionLine numberNew contents of line
be_bryan 0:b74591d5ab33 1
be_bryan 0:b74591d5ab33 2 /** \addtogroup events */
be_bryan 0:b74591d5ab33 3 /** @{*/
be_bryan 0:b74591d5ab33 4 /* events
be_bryan 0:b74591d5ab33 5 * Copyright (c) 2017 ARM Limited
be_bryan 0:b74591d5ab33 6 *
be_bryan 0:b74591d5ab33 7 * Licensed under the Apache License, Version 2.0 (the "License");
be_bryan 0:b74591d5ab33 8 * you may not use this file except in compliance with the License.
be_bryan 0:b74591d5ab33 9 * You may obtain a copy of the License at
be_bryan 0:b74591d5ab33 10 *
be_bryan 0:b74591d5ab33 11 * http://www.apache.org/licenses/LICENSE-2.0
be_bryan 0:b74591d5ab33 12 *
be_bryan 0:b74591d5ab33 13 * Unless required by applicable law or agreed to in writing, software
be_bryan 0:b74591d5ab33 14 * distributed under the License is distributed on an "AS IS" BASIS,
be_bryan 0:b74591d5ab33 15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
be_bryan 0:b74591d5ab33 16 * See the License for the specific language governing permissions and
be_bryan 0:b74591d5ab33 17 * limitations under the License.
be_bryan 0:b74591d5ab33 18 */
be_bryan 0:b74591d5ab33 19 #ifndef MBED_SHARED_QUEUES_H
be_bryan 0:b74591d5ab33 20 #define MBED_SHARED_QUEUES_H
be_bryan 0:b74591d5ab33 21
be_bryan 0:b74591d5ab33 22 #include "events/EventQueue.h"
be_bryan 0:b74591d5ab33 23
be_bryan 0:b74591d5ab33 24 namespace mbed {
be_bryan 0:b74591d5ab33 25
be_bryan 0:b74591d5ab33 26 /**
be_bryan 0:b74591d5ab33 27 * Return a pointer to an EventQueue, on which normal tasks can be queued.
be_bryan 0:b74591d5ab33 28 *
be_bryan 0:b74591d5ab33 29 * All calls to this return the same EventQueue - it and its dispatch thread
be_bryan 0:b74591d5ab33 30 * are created on the first call to this function. The dispatch thread
be_bryan 0:b74591d5ab33 31 * runs at default priority (currently osPriorityNormal).
be_bryan 0:b74591d5ab33 32 *
be_bryan 0:b74591d5ab33 33 * The EventQueue returned may be used to call() Events, or to chain() other
be_bryan 0:b74591d5ab33 34 * EventQueues so that they are run in the same context.
be_bryan 0:b74591d5ab33 35 *
be_bryan 0:b74591d5ab33 36 * Events (or chained EventQueues) executing on the normal event queue should
be_bryan 0:b74591d5ab33 37 * normally take less than 10ms to execute, to avoid starving other users. As
be_bryan 0:b74591d5ab33 38 * such, users can expect that event latency will typically be 10ms or less,
be_bryan 0:b74591d5ab33 39 * but could occasionally be significantly higher if many events are queued.
be_bryan 0:b74591d5ab33 40 *
be_bryan 0:b74591d5ab33 41 * If an RTOS is not present or the configuration option
be_bryan 0:b74591d5ab33 42 * `events.shared-dispatch-from-application` is set to true, then this
be_bryan 0:b74591d5ab33 43 * does not create a dedicated dispatch thread - instead the application is
be_bryan 0:b74591d5ab33 44 * expected to run the EventQueue's dispatch, eg from main. This is necessary
be_bryan 0:b74591d5ab33 45 * for the event loop to work without an RTOS, or an RTOS system can can save
be_bryan 0:b74591d5ab33 46 * memory by reusing the main stack.
be_bryan 0:b74591d5ab33 47 *
be_bryan 0:b74591d5ab33 48 * @return pointer to event queue
be_bryan 0:b74591d5ab33 49 */
be_bryan 0:b74591d5ab33 50 events::EventQueue *mbed_event_queue();
be_bryan 0:b74591d5ab33 51
be_bryan 0:b74591d5ab33 52 #ifdef MBED_CONF_RTOS_PRESENT
be_bryan 0:b74591d5ab33 53 /**
be_bryan 0:b74591d5ab33 54 * Return a pointer to an EventQueue, on which small high-priority tasks can
be_bryan 0:b74591d5ab33 55 * be queues, such as simple deferrals from interrupt.
be_bryan 0:b74591d5ab33 56 *
be_bryan 0:b74591d5ab33 57 * All calls to this return the same EventQueue - it and its thread are
be_bryan 0:b74591d5ab33 58 * created on the first call to this function. The dispatch thread
be_bryan 0:b74591d5ab33 59 * runs at a high priority (currently osPriorityHigh).
be_bryan 0:b74591d5ab33 60 *
be_bryan 0:b74591d5ab33 61 * The EventQueue returned may be used to call() Events, or to chain() other
be_bryan 0:b74591d5ab33 62 * EventQueues so that they are run in the same context.
be_bryan 0:b74591d5ab33 63 *
be_bryan 0:b74591d5ab33 64 * Events (or chained EventQueues) executing on the high-priority event queue
be_bryan 0:b74591d5ab33 65 * should normally take less than 100us to execute, to avoid starving other
be_bryan 0:b74591d5ab33 66 * users. As such, users can expect that event latency will typically be 100us
be_bryan 0:b74591d5ab33 67 * or less, but could occasionally be significantly higher if many events are
be_bryan 0:b74591d5ab33 68 * queued.
be_bryan 0:b74591d5ab33 69 *
be_bryan 0:b74591d5ab33 70 * @return pointer to high-priority event queue
be_bryan 0:b74591d5ab33 71 */
be_bryan 0:b74591d5ab33 72
be_bryan 0:b74591d5ab33 73 events::EventQueue *mbed_highprio_event_queue();
be_bryan 0:b74591d5ab33 74
be_bryan 0:b74591d5ab33 75 #endif // MBED_CONF_RTOS_PRESENT
be_bryan 0:b74591d5ab33 76
be_bryan 0:b74591d5ab33 77 };
be_bryan 0:b74591d5ab33 78
be_bryan 0:b74591d5ab33 79 #endif
be_bryan 0:b74591d5ab33 80
be_bryan 0:b74591d5ab33 81 /** @}*/