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-rw-r--r--TaskScheduler.cpp7
-rw-r--r--TaskScheduler.h9
-rw-r--r--documentation/TaskScheduler.docbin61952 -> 65024 bytes
-rw-r--r--documentation/TaskScheduler.htm2112
4 files changed, 849 insertions, 1279 deletions
diff --git a/TaskScheduler.cpp b/TaskScheduler.cpp
index 317b70c..924b40e 100644
--- a/TaskScheduler.cpp
+++ b/TaskScheduler.cpp
@@ -1,4 +1,4 @@
-// Cooperative multitasking library for Arduino version 1.51
+// Cooperative multitasking library for Arduino version 1.6
// Copyright (c) 2015 Anatoli Arkhipenko
//
@@ -50,7 +50,6 @@ void Task::reset() {
iPrev = NULL;
iNext = NULL;
iScheduler = NULL;
- iDisableOnLastIteration = false;
#ifdef _TASK_TIMECRITICAL
iOverrun = 0;
#endif
@@ -63,7 +62,6 @@ void Task::reset() {
*/
void Task::set(unsigned long aInterval, long aIterations, void (*aCallback)()) {
iInterval = aInterval;
- if (iEnabled && iIterations == 0) enable();
iSetIterations = iIterations = aIterations;
iCallback = aCallback;
}
@@ -73,7 +71,6 @@ void Task::set(unsigned long aInterval, long aIterations, void (*aCallback)()) {
* @param aIterations - number of iterations, use -1 for no limit
*/
void Task::setIterations(long aIterations) {
- if (iEnabled && iIterations == 0) enable();
iSetIterations = iIterations = aIterations;
}
@@ -240,7 +237,7 @@ void Scheduler::execute() {
do {
if (iCurrent->iEnabled) {
if (iCurrent->iIterations == 0) {
- if (iCurrent->iDisableOnLastIteration) iCurrent->disable();
+ iCurrent->disable();
break;
}
if (iCurrent->iInterval > 0) {
diff --git a/TaskScheduler.h b/TaskScheduler.h
index fae04ce..fe09bb5 100644
--- a/TaskScheduler.h
+++ b/TaskScheduler.h
@@ -1,4 +1,4 @@
-// Cooperative multitasking library for Arduino version 1.51
+// Cooperative multitasking library for Arduino version 1.6
// Copyright (c) 2015 Anatoli Arkhipenko
//
// Changelog:
@@ -20,6 +20,11 @@
// v1.51:
// 2015-09-21 - bug fix: incorrect handling of active tasks via set() and setIterations().
// Thanks to Hannes Morgenstern for catching this one
+// v1.6:
+// 2015-09-22 - revert back to having all tasks disable on last iteration.
+// 2015-09-22 - deprecated disableOnLastIteration method as a result
+// 2015-09-22 - created a separate branch 'disable-on-last-iteration' for this
+
/* ============================================
@@ -105,7 +110,6 @@ class Task {
void setIterations(long aIterations);
inline long getIterations() { return iIterations; }
inline void setCallback(void (*aCallback)()) { iCallback = aCallback; }
- inline void disableOnLastIteration(bool aBool) { iDisableOnLastIteration = aBool; } // default is false
#ifdef _TASK_TIMECRITICAL
inline long getOverrun() { return iOverrun; }
#endif
@@ -116,7 +120,6 @@ class Task {
void reset();
volatile bool iEnabled;
- volatile bool iDisableOnLastIteration;
volatile unsigned long iInterval;
volatile unsigned long iPreviousMillis;
#ifdef _TASK_TIMECRITICAL
diff --git a/documentation/TaskScheduler.doc b/documentation/TaskScheduler.doc
index 9c7e7a8..36425ea 100644
--- a/documentation/TaskScheduler.doc
+++ b/documentation/TaskScheduler.doc
Binary files differ
diff --git a/documentation/TaskScheduler.htm b/documentation/TaskScheduler.htm
index 38b822a..34aadaf 100644
--- a/documentation/TaskScheduler.htm
+++ b/documentation/TaskScheduler.htm
@@ -1,1271 +1,841 @@
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-
-<p class=MsoNormal><b>Task Scheduler – cooperative multitasking for Arduino microcontrollers</b></p>
-
-<p class=MsoNormal><b>Version 1.51: 2015-09-20</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>REQUIREMENT</b>:</p>
-
-<p class=MsoNormal>A lightweight implementation of the task scheduling
-supporting:</p>
-
-<ol style='margin-top:0in' start=1 type=1>
- <li class=MsoNormal>execution period (n times per second)</li>
- <li class=MsoNormal>number of iterations (n times)</li>
- <li class=MsoNormal>execution of tasks in predefined sequence</li>
- <li class=MsoNormal>dynamic change of the execution parameters for both tasks
- and execution schedule</li>
- <li class=MsoNormal>power saving via entering IDLE sleep mode if no tasks are
- scheduled to run</li>
-</ol>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>IDEA</b>:</p>
-
-<p class=MsoNormal>“Task” is a container concept that links together:</p>
-
-<ol style='margin-top:0in' start=1 type=1>
- <li class=MsoNormal>Execution interval</li>
- <li class=MsoNormal>Number of execution iterations</li>
- <li class=MsoNormal>A piece of code performing the task activities (callback
- function)</li>
-</ol>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>Tasks are linked into execution chains, which are processed
-by the “Scheduler” in the order they are linked.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>Tasks are responsible for supporting cooperative
-multitasking by being “good neighbors”, i.e., running their callback functions
-in a non-blocking way and releasing control as soon as possible. </p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>“Scheduler” is executing Tasks' callback functions in the
-order the tasks were added to the chain, from first to last. Scheduler stops
-and exists after processing the chain once in order to allow other statements
-in the main code of <b>loop()</b> function to run.&nbsp; This a “scheduling
-pass”.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>If compiled with <span style='font-family:"Courier New"'>_TASK_SLEEP_ON_IDLE_RUN</span>
-enabled, the scheduler will place processor into IDLE sleep mode (for
-approximately 1 ms, as the timer interrupt will wake it up), after what is
-determined to be an “idle” pass. An Idle Pass is a pass through the chain when
-no Tasks were scheduled to run their callback functions. This is done to avoid
-repetitive empty passes through the chain when no tasks need to be executed. If
-any of the tasks in the chain always requires immediate execution (aInterval =
-0), then there will be no end-of-pass delay.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>Note: </b>Task Scheduler uses <b>millis()</b> to
-determine if tasks are ready to be invoked. Therefore, if you put your device
-to any “deep” sleep mode disabling timer interrupts, the <b>millis()</b> count
-will be suspended, leading to effective suspension of scheduling. Upon wake up,
-active tasks need to be re-enabled, which will effectively reset their internal
-time scheduling variables to the new value of <b>millis(). </b>Time spent in
-deep sleep mode should be considered “frozen”, i.e., if a task was scheduled to
-run in 1 second from now, and device was put to sleep for 5 minutes, upon wake
-up, the task will still be scheduled 1 second from the time of wake up.
-Executing <b>enable() </b>function on this tasks will make it run as soon as
-possible. This is a concern only for tasks which are required to run in a truly
-periodical manner (in absolute time terms). </p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>COMPILE PARAMETERS:</b></p>
-
-<p class=MsoNormal>This library could be compiled with several options. </p>
-
-<p class=MsoNormal>These parameters must be defined before inclusion of the
-library header file into the sketch.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>#define <b>_TASK_TIMECRITICAL</b></p>
-
-<p class=MsoNormal>...will compile the library with time critical tracking
-option enabled.</p>
-
-<p class=MsoNormal>Time critical option keeps track where next execution time
-of the task falls, and makes it available via API through Task::<b> getOverrun()
-</b>function. If <b>getOverrun </b>returns a negative value, this Task’s next
-execution time is in the past, and task is behind schedule. This most probably
-means that either task’s callback function runtime is too long, or the
-execution interval is too short (then schedule is too aggressive).</p>
-
-<p class=MsoNormal>A positive value indicates that task is on schedule, and
-callback functions have enough time to finish before the next scheduled pass. </p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>#define <b>_TASK_SLEEP_ON_IDLE_RUN</b></p>
-
-<p class=MsoNormal>...will compile the library with the <b>sleep</b> option
-enabled (AVR boards only).</p>
-
-<p class=MsoNormal>When enabled, scheduler will put the microcontroller into <b>SLEEP_MODE_IDLE</b>
-state if none of the tasks’ callback functions were activated during pass. <b>IDLE</b>
-state is interrupted by timers once every 1 ms. Helps conserve power. &nbsp;Device
-in SLEEP_MODE_IDLE wakes up to all hardware and timer interrupts, so scheduling
-is kept current.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>NOTE: above parameters are DISABLED by default, and need
-to be explicitly enabled.</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>API DOCUMENTATION:</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>TASKS:</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>CREATION:</p>
-
-<p class=MsoNormal><b>Task();</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Default constructor. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Takes no parameters and creates
-a task that could be scheduled to run at every scheduling pass indefinitely,
-but does not have a callback function defined, so no execution will actually
-take place. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>All tasks are created <b>disabled</b>
-by default.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='page-break-after:avoid'><b>Task(unsigned long aInterval,
-long aIterations, void (*aCallback)(), Scheduler* aScheduler, bool aEnable);</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Constructor with parameters. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Creates a task that is scheduled
-to run every &lt;aInterval&gt; milliseconds, &lt;aIterations&gt; times,
-executing &lt;aCallback&gt; function on every pass. </p>
-
-<p class=MsoNormal style='margin-left:71.45pt;text-indent:-.25in'>1.<span
-style='font-size:7.0pt;font-family:"Times New Roman","serif"'>&nbsp;&nbsp;&nbsp;
-</span>aInterval is in milliseconds</p>
-
-<p class=MsoNormal style='margin-left:71.45pt;text-indent:-.25in'>2.<span
-style='font-size:7.0pt;font-family:"Times New Roman","serif"'>&nbsp;&nbsp;&nbsp;
-</span>aIteration in number of times, -1 for indefinite execution<br>
-<b>Note: </b>Tasks do not remember the number of iteration set initially. After
-the iterations are done, internal iteration counter is 0. If you need to
-perform another set of iterations, you need to set the number of iterations
-again. <br>
-<b>Note: </b>Tasks which performed all their iterations remain active. </p>
-
-<p class=MsoNormal style='margin-left:71.45pt;text-indent:-.25in'>3.<span
-style='font-size:7.0pt;font-family:"Times New Roman","serif"'>&nbsp;&nbsp;&nbsp;
-</span>aCallback is a pointer to a void function without parameters</p>
-
-<p class=MsoNormal style='margin-left:71.45pt;text-indent:-.25in'>4.<span
-style='font-size:7.0pt;font-family:"Times New Roman","serif"'>&nbsp;&nbsp;&nbsp;
-</span>aScheduler – <b>optional</b> reference to existing scheduler. If
-supplied (not NULL) this task will be appended to the task chain of the current
-scheduler). <b>Default=NULL</b></p>
-
-<p class=MsoNormal style='margin-left:71.45pt;text-indent:-.25in'>5.<span
-style='font-size:7.0pt;font-family:"Times New Roman","serif"'>&nbsp;&nbsp;&nbsp;
-</span>aEnable – <b>optional</b>. Value of <b>true </b>will create task
-enabled. <b>Default = false</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>All tasks are created <b>disabled</b>
-by default (unless aEnable = true). You have to explicitly enable the task for
-execution.</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Enabled task is scheduled for execution
-immediately. Enable tasks with delay (standard execution interval or specific
-execution interval) in order to defer first run of the task.</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>INFORMATION</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>The following 3 “getter”
-functions return task status (enabled/disabled), execution interval in
-milliseconds, number of <b><i>remaining</i></b> iterations. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>bool isEnabled() </b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>unsigned long getInterval()</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>long getIterations() </b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>&nbsp;</b></p>
-
-<p class=MsoNormal><b>long getOverrun()</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>If library is compiled with <span
-style='font-family:"Courier New"'>_TASK_TIMECRITICAL</span> enabled, tasks are
-monitored for “long running” scenario. A “long running” task is a task that
-does not finish processing its callback functions quickly, and thus creates a
-situation for itself and other tasks where they don't run on a scheduled
-interval, but rather “catch up” and are behind.&nbsp; When task scheduler sets
-the next execution target time, it adds Task's execution interval to the
-previously scheduled execution time:</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
-<b>next execution time = previous execution time + task execution interval</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>If <b>next execution time</b> happens
-to be already in the past (<b>next execution time</b> &lt; <b>millis()</b>), then
-task is considered <b><i>overrun</i></b>. <b>GetOverrun</b> function returns
-number of milliseconds between next execution time and current time. If the <b>value
-is negative</b>, the task is overrun by that many milliseconds. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Positive value indicate number
-of milliseconds of slack this task has for execution purposes. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>bool isFirstIteration()</b></p>
-
-<p class=MsoNormal><b>bool isLastIteration()</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>For tasks with a defined number
-of iterations, indicates whether current pass is a first or a last iteration of
-the task (respectively). </p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='page-break-after:avoid'><b>CONTROL:</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>void enable();</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Enables the task, and schedules
-it for immediate execution (without delay) at this or next scheduling pass
-depending on when the task was enabled. Scheduler will execute the next pass
-without any delay because there is a task which was enabled and requires
-execution. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void delay();</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Schedules the task for execution
-after a delay (aInterval), but does not change the enabled/disabled status of
-the task. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>&nbsp;</b></p>
-
-<p class=MsoNormal><b>void enableDelayed();</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Enables the task, and schedules
-it for execution after a delay (aInterval). </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void enableDelayed (unsigned long aDelay);</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Enables the task, and schedules
-it for execution after a specific delay (aDelay, which maybe different from aInterval).
-</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void restart();</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>For tasks with limited number of
-iterations only, <b>restart</b> function will re-enable the task, set the
-number of iterations back to when the task was created and and schedule the
-task for execution as soon as possible.</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void restartDelayed (unsigned long aDelay);</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Same as <b>restart() </b>function,
-with the only difference being that Task is scheduled to run first iteration
-after a delay = <b>aDelay</b> milliseconds.</p>
-
-<p class=MsoNormal><b>&nbsp;</b></p>
-
-<p class=MsoNormal><b>void disable();</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Disables the task. Scheduler
-will not execute this task any longer, even if it remains in the chain.&nbsp; Task
-can be later re-enabled for execution. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void disableOnLastIteration (bool aBool);</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Controls iterative task behavior
-on the last iteration. If <b>aBool</b> is <b>true</b> task will be disabled
-after last iteration. If <b>aBool</b> is <b>false</b>, task will remain active
-(but not invoked until new number of iterations is set)</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>void set(unsigned long aInterval, long aIterations, void (*aCallback)());</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Allows dynamic control of all
-task execution parameters in one function call. If task being modified is
-active, it will be scheduled for execution immediately. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal>Next three “setter” functions allow changes of individual
-task execution control parameters. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>void setInterval (unsigned
-long aInterval) </b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>void setIterations (long aIterations)
-</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>void setCallback (void
-(*aCallback)()) </b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>Note: </b>Next execution time calculation takes place <b>after</b>
-the callback function is called, so new interval will be used immediately by
-the scheduler. For the situations when one task is changing the interval
-parameter for the other, <b>setInterval</b> function calls <b>delay </b>explicitly
-to guarantee schedule change, however it <b>does not </b>enable the task if
-task is disabled. If task being modified is active, <b>setIterations </b>will
-make the task be scheduled for execution immediately.</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>&nbsp;</b></p>
-
-<p class=MsoNormal><b>TASK SCHEDULER:</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><b>CREATION:</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-bottom:12.0pt'><b>Scheduler()</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Default constructor. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Takes no parameters. Creates
-task scheduler with default parameters and an empty task queue. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void init()</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Initializes the task queue and
-scheduler parameters, Executed as part of constructor, so don't need to be
-explicitly called after creation.</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>Note: </b>be default (if
-compiled with <span style='font-family:"Courier New"'>_TASK_TIMECRITICAL</span>
-enabled) scheduler is allowed to put processor to IDLE sleep mode. If this
-behavior was changed via <b>allowSleep() </b>function, <b>inti() </b>will <b>NOT</b>
-reset allow sleep particular parameter. </p>
-
-<p class=MsoNormal><br>
-<b>void addTask(Task&amp; aTask)</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Adds task aTask to the execution
-queue (or chain) of tasks by appending it to the end of the chain. If two tasks
-are scheduled for execution, the sequence will match the order tasks are
-appended to the chain. However, in reality, due to different timing of task
-execution, the actual order will be different. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>Note: </b>Currently, changing
-the execution dynamically is not supported. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>If you need to reorder the queue
-– initialize the scheduler and re-add the tasks in a different order. </p>
-
-<p class=MsoNormal><br>
-<b>void deleteTask(Task&amp; aTask)</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Deletes task aTask from the
-execution chain. The chain of remaining tasks is linked together (i.e</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>if original task chain is 1 &#8594;
-2 &#8594; 3 &#8594; 4, deleting 3 will result in 1 &#8594; 2 &#8594; 4).</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><b>Note: </b>it is not required
-to delete a task from the chain. A disabled task will not be executed anyway,
-but you save a few microseconds per scheduling pass by deleting it, since it is
-not even considered for execution. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>An example of proper use of this
-function would be running some sort of <b>initialize</b> task in the chain, and
-then deleting it from the chain since it only needs to run once. </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal><b>void allowSleep(bool aState) </b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Available in API only&nbsp; if compiled
-with <span style='font-family:"Courier New"'>_TASK_TIMECRITICAL</span> enabled.
-Controls whether scheduler is allowed (<b>aState =true</b>), or not (<b>aState =false</b>)
-to put processor into IDLE sleep mode in case not tasks are scheduled to run.</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>The <b>default</b> behavior of
-scheduler upon creation is to allow sleep mode. </p>
-
-<p class=MsoNormal><br>
-<b>void enableAll()</b></p>
-
-<p class=MsoNormal><b>void disableAll()</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>enables and disables
-(respectively) all tasks in the chain. Convenient if your need to
-enable/disable majority of the tasks (i.e. disable all and then enable one). </p>
-
-<p class=MsoNormal style='margin-bottom:12.0pt'><br>
-<b>Task&amp; currentTask()</b></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Returns reference to the task,
-currently executing via <b>execute()</b> loop. Could be used by callback
-functions to identify which of the </p>
-
-<p class=MsoNormal><br>
-<b>void execute()</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>Executes one scheduling pass,
-including end-of-pass sleep. This function typically placed inside the <b>loop()</b>
-function of the sketch. Since <b>execute</b> exits after every pass, you can
-put additional statements after <b>execute</b> inside the <b>loop()</b> </p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'>&nbsp;</p>
-
-<p class=MsoNormal style='page-break-after:avoid'><b>IMPLEMENTATION SCENARIOS
-AND IDEAS:</b></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<ol style='margin-top:0in' start=1 type=1>
- <li class=MsoNormal><b>EVENT DRIVEN PROGRAMMING</b></li>
-</ol>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>Each of the processes of your application becomes a separate
-and distinct programming area, which may or may not interact and control each
-other. </p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal>Example: </p>
-
-<p class=MsoNormal>In a plant watering system you need to measure soil
-humidity, control pump and display the results</p>
-
-<p class=MsoNormal>Each of the areas becomes a task:</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>Task
-<b>tMeasure</b> (TMEASURE_INTERVAL*SECOND, -1, &amp;measureCallback);<br>
-Task <b>tWater</b>&nbsp;&nbsp; (TWATER_INTERVAL*SECOND, RETRIES,
-&amp;waterCallback);<br>
-Task <b>tDisplay</b> (TDISPLAY_INTERVAL*SECOND, -1, &amp;displayCallback); </span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>Scheduler
-<b>taskManager</b>;</span></p>
-
-<p class=MsoNormal>Further, once you turn on the pump, you keep it running for
-TWATER_INTERVAL interval and then turn it off. Turning off a pump is also a
-task which only needs to run once for every time the pump is turned on:</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>Task
-<b>tWaterOff</b> (WATERTIME*SECOND, 1,</span><span style='font-family:"Courier New"'>
-&amp;waterOffCallback);</span></p>
-
-<p class=MsoNormal>Example of the callback function:</p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>void waterOffCallback() {<br>
-&nbsp;&nbsp;&nbsp; motorOff();<br>
-&nbsp;&nbsp;&nbsp; tWater.enableDelayed();<br>
-}</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>or</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>void waterCallback() {<br>
-&nbsp;&nbsp;&nbsp; if (tWater.getIterations()) {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>// If this is not the last iteration = turn the pump
-on<br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; motorOn();<br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tWaterOff.set(parameters.watertime * SECOND, 1,
-&amp;waterOffCallback);<br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tWaterOff.enableDelayed();<br>
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return;<br>
-&nbsp;&nbsp;&nbsp; }</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>// We could not reach target humidity – something is
-wrong<br>
-&nbsp;&nbsp;&nbsp; motorOff;<br>
-&nbsp;&nbsp;&nbsp; taskManager.disableAll();<br>
-&nbsp;&nbsp;&nbsp; tError.enable();<br>
-}</span></p>
-
-<p class=MsoNormal><span style='font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Your
-sample <b>setup</b>() and <b>loop</b>() (partially) are as follows. </span></p>
-
-<p class=MsoNormal><b><span style='font-family:"Times New Roman","serif"'>Note:
-</span></b><span style='font-family:"Times New Roman","serif"'>please note that
-tWater is <b>not</b> activated during setup(). It is activated by tMeasure
-callback once the watering conditions are met. </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
-</span><span style='font-family:"Courier New"'>setup()</span></p>
-
-<p class=MsoNormal><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-&nbsp; ...</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;
-tWater.setIterations(parameters.retries);<br>
-&nbsp; tWaterOff.setInterval(parameters.watertime * SECOND);<br>
-<br>
-<br>
-&nbsp; taskManager.init();<br>
-&nbsp; taskManager.addTask(tMeasure);<br>
-&nbsp; taskManager.addTask(tDisplay);<br>
-&nbsp; taskManager.addTask(tWater);<br>
-&nbsp; taskManager.addTask(tWaterOff);<br>
-&nbsp; <br>
-&nbsp; tMeasure.enable();<br>
-&nbsp; tDisplay.enable();<br>
-<br>
-&nbsp; currentHumidity = measureHumidity();<br>
-}<br>
-<br>
-<br>
-void loop ()<br>
-{<br>
-&nbsp; taskManager.execute();<br>
-}</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'>&nbsp;</p>
-
-<ol style='margin-top:0in' start=2 type=1>
- <li class=MsoNormal><b><span style='font-family:"Times New Roman","serif"'>“NATIVE”
- SUPPORT FOR FINITE STATE MACHINE</span></b></li>
-</ol>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Define
-“states” as callback function or functions. Each callback function executes
-activities specific to a “state” and then “transitions” to the next state by
-assigning next callback function to the task. </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Transition
-from one state to the next is achieved by setting next callback function at the
-end of preceding one. </span></p>
-
-<p class=MsoNormal><b><span style='font-family:"Times New Roman","serif"'>Note:
-</span></b><span style='font-family:"Times New Roman","serif"'>do not call the
-next callback function. Let the schedule take care of that during the next
-pass. (Thus letting other tasks run). </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Example:
-Blinking LED 2 times a second could be achieved this way</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>Task
-tLedBlinker (500, -1, &amp;ledOnCallback);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>Scheduler
-taskManager;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>void&nbsp;
-ledOnCallback() {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-turnLedOn();</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-tLedBlinker.setCallback(&amp;ledOffCallback);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>void&nbsp;
-ledOffCallback() {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-turnLedOff();</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-tLedBlinker.setCallback(&amp;ledOnCallback);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>setup()
-{</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-taskManager.init();<br>
-&nbsp; &nbsp;&nbsp; taskManager.addTask(tLedBlinker);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-tLedBlinker.enable();</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>loop
-() {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;
-taskManager.execute();</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Obviously
-the example is simple, but gives the idea of how the tasks could be used to go
-through states.</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<ol style='margin-top:0in' start=3 type=1>
- <li class=MsoNormal><b><span style='font-family:"Times New Roman","serif"'>MULTIPLE
- POSSIBLE CALLBACKS FOR TASK</span></b></li>
-</ol>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>There may
-be a need to select an option for callback function based on certain criteria,
-or randomly. </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>You can
-achieve that by defining an array of callback function pointers and selecting
-one based on the criteria you need. </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Example:
-when a robot detects an obstacle, it may go left, right backwards, etc. Each of
-the “directions” or “behaviors” are represented by a different callback
-function. </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Another
-example of using multiple callbacks:</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>You may
-need to “initialize” variables for a particular task.</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>In this
-case, define a tasks with two callbacks:</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>Task <b>tWork</b> (T_INTERVAL, -1,
-&amp;workCallbackInit);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>…</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>void&nbsp; workCallbackInit() {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // do your
-initializationstuff here</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // finally assigne
-the main callback function </span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
-tWork.setCallback(&amp;workCallback);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>void workCallback() {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // main callback
-function</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; …</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>The task
-will initialize during first execution pass and switch to “regular” callback
-execution starting with second pass. There is a delay between first and second
-passes of the task (scheduling period, if defined). In order to execute the
-second pass immediately after initialization first pass, change the above code
-like this:</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>void&nbsp; workCallbackInit() {</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // do your
-initializationstuff here</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // finally assigne the
-main callback function </span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
-tWork.setCallback(&amp;workCallback);</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tWork.enable();</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>}</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>The task
-will run initialization first, then immediately second pass, and then switch to
-processing at regular intervals starting with a third pass. </span></p>
-
-<p class=MsoNormal>&nbsp;</p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<ol style='margin-top:0in' start=4 type=1>
- <li class=MsoNormal><b><span style='font-family:"Times New Roman","serif"'>INTERRUP-DRIVEN
- EXECUTION SUPPORT </span></b></li>
-</ol>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>In case
-of interrupt-driven program flow, tasks could be scheduled to run once to
-request asynchronous execution (request), and then re-enabled (restarted) again
-with a different callback function to process the results. </span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal><b><span style='font-family:"Times New Roman","serif"'>Example</span></b><span
-style='font-family:"Times New Roman","serif"'>: event driven distance
-calculation for ultrasonic pulses. EchoPin #6 triggers pin change interrupts on
-rising and falling edges to determine the length of ultrasonic pulse.</span></p>
-
-<p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>&nbsp;</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>#include &lt;DirectIO.h&gt;<br>
-#include &lt;TaskScheduler.h&gt;<br>
-#include &lt;PinChangeInt.h&gt;<br>
-<br>
-<br>
-#define&nbsp; TRIGGERPIN 5<br>
-#define&nbsp; ECHOPIN&nbsp;&nbsp;&nbsp; 6<br>
-<br>
-Output&lt;TRIGGERPIN&gt;&nbsp; pTrigger;<br>
-Input&lt;ECHOPIN&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; pEcho;<br>
-<br>
-Scheduler r;<br>
-<br>
-Task&nbsp; tMeasure(1000, -1, &amp;measureCallback);<br>
-Task&nbsp; tDisplay(1000, -1, &amp;displayCallback);<br>
-Task&nbsp; tPing(0, 1, &amp;pingCalcCallback);<br>
-<br>
-<br>
-volatile bool pulseBusy = false;<br>
-volatile bool pulseTimeout = false;<br>
-volatile unsigned long pulseStart = 0;<br>
-volatile unsigned long pulseStop = 0;<br>
-volatile unsigned long pingDistance = 0;<br>
-<br>
-<br>
-void pingTrigger(unsigned long aTimeout) {<br>
-&nbsp; if (pulseBusy) return;&nbsp; // do not trigger if in the middle of a
-pulse<br>
-&nbsp; if (pEcho == HIGH) return; // do not trigger if ECHO pin is high<br>
-&nbsp; <br>
-&nbsp; pulseBusy = true;<br>
-&nbsp; pulseTimeout = false;</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'><br>
-&nbsp; pTrigger = LOW;<br>
-&nbsp; delayMicroseconds(4);<br>
-&nbsp; pTrigger = HIGH;<br>
-<br>
-&nbsp; tPing.setInterval (aTimeout);<br>
-<br>
-&nbsp; delayMicroseconds(10);<br>
-&nbsp; pTrigger = LOW; </span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>&nbsp;
-tPing.restartDelayed(); // timeout countdown starts now</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>// will start the pulse clock on the rising edge of
-ECHO pin</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>&nbsp;
-PCintPort::attachInterrupt(ECHOPIN, &amp;pingStartClock, RISING); <br>
-}<br>
-<br>
-</span></p>
-
-<p class=MsoNormal style='margin-left:35.45pt'><span style='font-size:10.0pt;
-font-family:"Courier New"'>// Start clock on the <b>rising</b> edge of the
-ultrasonic pulse<br>
-void pingStartClock() {<br>
-&nbsp; pulseStart = micros();<br>
-&nbsp; PCintPort::detachInterrupt(ECHOPIN); // not sure this is necessary<br>
-&nbsp; PCintPort::attachInterrupt(ECHOPIN, &amp;pingStopClock, FALLING); <br>
-&nbsp; tPing.restartDelayed();<br>
-}<br>
-<br>
-// Stop clock on the <b>falling</b> edge of the ultrasonic pulse<br>
-void pingStopClock() {<br>
-&nbsp; pulseStop = micros();<br>
-&nbsp; PcintPort::detachInterrupt(ECHOPIN);</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>&nbsp;
-pingDistance = pulseStop - pulseStart;<br>
-&nbsp; pulseBusy = false;<br>
-&nbsp; tPing.disable(); // disable timeout<br>
-}</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>//
-Stop clock because of the timeout – the wave did not return<br>
-void pingCalcCallback() {<br>
-&nbsp; if (pulseBusy) {<br>
-&nbsp;&nbsp;&nbsp; pingStopClock();<br>
-&nbsp; }<br>
-&nbsp; pulseTimeout = true;<br>
-}<br>
-<br>
-<br>
-<br>
-// Initial measure callback sets the trigger<br>
-void measureCallback() {<br>
-&nbsp; if (pulseBusy) {&nbsp; // already measuring, try again<br>
-&nbsp;&nbsp;&nbsp; tMeasure.enable();<br>
-&nbsp;&nbsp;&nbsp; return;<br>
-&nbsp; }<br>
-&nbsp; pingTrigger(30); // 30 milliseconds or max range of ~5.1 meters<br>
-&nbsp; tMeasure.setCallback(&amp;measureCallbackWait);<br>
-}</span></p>
-
-<p class=MsoNormal style='margin-top:0in;margin-right:0in;margin-bottom:12.0pt;
-margin-left:35.45pt'><span style='font-size:10.0pt;font-family:"Courier New"'>//
-Wait for the measurement to <br>
-void measureCallbackWait() {<br>
-&nbsp; if (pulseBusy) return;<br>
-&nbsp; tMeasure.setCallback(&amp;measureCallback);&nbsp; <br>
-}<br>
-<br>
-<br>
-bool state = true;<br>
-<br>
-void displayCallback() {<br>
-&nbsp; char d[256];<br>
-&nbsp;&nbsp; <br>
-&nbsp; unsigned long cm = pingDistance * 17 / 100; // cm<br>
-&nbsp; <br>
-&nbsp; snprintf(d, 256, &quot;pulseStart = %8lu\tpulseStop=%8lu\tdistance,
-cm=%8lu&quot;, pulseStart, pulseStop, cm);<br>
-&nbsp; Serial.println(d);<br>
-&nbsp; <br>
-}<br>
-<br>
-void setup() {<br>
-&nbsp; // put your setup code here, to run once:<br>
-&nbsp; <br>
-&nbsp; Serial.begin(115200);<br>
-&nbsp; <br>
-<br>
-&nbsp; pTrigger = LOW;<br>
-&nbsp; pEcho = LOW;<br>
-&nbsp; <br>
-&nbsp; r.init();<br>
-&nbsp; r.addTask(tDisplay);<br>
-&nbsp; r.addTask(tMeasure);<br>
-&nbsp; r.addTask(tPing);<br>
-&nbsp; <br>
-&nbsp; r.enableAll();<br>
-&nbsp; tPing.disable();<br>
-}<br>
-<br>
-void loop() {<br>
-&nbsp; // put your main code here, to run repeatedly:<br>
-&nbsp; r.execute();<br>
-}</span></p>
-
-</div>
-
-</body>
-
-</html>
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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+<BODY LANG="en-US" TEXT="#000000" DIR="LTR">
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Task Scheduler –
+cooperative multitasking for Arduino microcontrollers</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Version 1.6:
+2015-09-22</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>REQUIREMENT</B>:</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">A lightweight
+implementation of the task scheduling supporting:</P>
+<OL>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">execution period
+ (n times per second)</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">number of
+ iterations (n times)</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">execution of tasks
+ in predefined sequence</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">dynamic change of
+ the execution parameters for both tasks and execution schedule</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">power saving via
+ entering IDLE sleep mode if no tasks are scheduled to run</P>
+</OL>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>IDEA</B>:</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">“Task” is a
+container concept that links together:</P>
+<OL>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">Execution interval</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">Number of
+ execution iterations</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">A piece of code
+ performing the task activities (callback function)</P>
+</OL>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Tasks are linked into
+execution chains, which are processed by the “Scheduler” in the
+order they are linked.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Tasks are responsible
+for supporting cooperative multitasking by being “good neighbors”,
+i.e., running their callback functions in a non-blocking way and
+releasing control as soon as possible.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">“Scheduler” is
+executing Tasks' callback functions in the order the tasks were added
+to the chain, from first to last. Scheduler stops and exists after
+processing the chain once in order to allow other statements in the
+main code of <B>loop()</B> function to run. This a “scheduling
+pass”.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">If compiled with
+<FONT FACE="Courier New, monospace">_TASK_SLEEP_ON_IDLE_RUN</FONT>
+enabled, the scheduler will place processor into IDLE sleep mode (for
+approximately 1 ms, as the timer interrupt will wake it up), after
+what is determined to be an “idle” pass. An Idle Pass is a pass
+through the chain when no Tasks were scheduled to run their callback
+functions. This is done to avoid repetitive empty passes through the
+chain when no tasks need to be executed. If any of the tasks in the
+chain always requires immediate execution (aInterval = 0), then there
+will be no end-of-pass delay.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Note: </B>Task
+Scheduler uses <B>millis()</B> to determine if tasks are ready to be
+invoked. Therefore, if you put your device to any “deep” sleep
+mode disabling timer interrupts, the <B>millis()</B> count will be
+suspended, leading to effective suspension of scheduling. Upon wake
+up, active tasks need to be re-enabled, which will effectively reset
+their internal time scheduling variables to the new value of
+<B>millis(). </B>Time spent in deep sleep mode should be considered
+“frozen”, i.e., if a task was scheduled to run in 1 second from
+now, and device was put to sleep for 5 minutes, upon wake up, the
+task will still be scheduled 1 second from the time of wake up.
+Executing <B>enable() </B>function on this tasks will make it run as
+soon as possible. This is a concern only for tasks which are required
+to run in a truly periodical manner (in absolute time terms).
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>COMPILE PARAMETERS:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in">This library could be
+compiled with several options.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">These parameters must
+be defined before inclusion of the library header file into the
+sketch.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">#define
+<B>_TASK_TIMECRITICAL</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in">...will compile the
+library with time critical tracking option enabled.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Time critical option
+keeps track where next execution time of the task falls, and makes it
+available via API through Task::<B> getOverrun() </B>function. If
+<B>getOverrun </B>returns a negative value, this Task’s next
+execution time is in the past, and task is behind schedule. This most
+probably means that either task’s callback function runtime is too
+long, or the execution interval is too short (then schedule is too
+aggressive).</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">A positive value
+indicates that task is on schedule, and callback functions have
+enough time to finish before the next scheduled pass.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">#define
+<B>_TASK_SLEEP_ON_IDLE_RUN</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in">...will compile the
+library with the <B>sleep</B> option enabled (AVR boards only).</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">When enabled, scheduler
+will put the microcontroller into <B>SLEEP_MODE_IDLE</B> state if
+none of the tasks’ callback functions were activated during pass.
+<B>IDLE</B> state is interrupted by timers once every 1 ms. Helps
+conserve power. Device in SLEEP_MODE_IDLE wakes up to all hardware
+and timer interrupts, so scheduling is kept current.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>NOTE: above
+parameters are DISABLED by default, and need to be explicitly
+enabled.</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>API DOCUMENTATION:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>TASKS:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">CREATION:</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Task();</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Default
+constructor.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Takes
+no parameters and creates a task that could be scheduled to run at
+every scheduling pass indefinitely, but does not have a callback
+function defined, so no execution will actually take place.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">All
+tasks are created <B>disabled</B> by default.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in; page-break-after: avoid">
+<B>Task(unsigned long aInterval, long aIterations, void
+(*aCallback)(), Scheduler* aScheduler, bool aEnable);</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Constructor
+with parameters.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Creates
+a task that is scheduled to run every &lt;aInterval&gt; milliseconds,
+&lt;aIterations&gt; times, executing &lt;aCallback&gt; function on
+every pass.
+</P>
+<OL>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">aInterval is in
+ milliseconds</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">aIteration in
+ number of times, -1 for indefinite execution<BR><B>Note: </B>Tasks
+ do not remember the number of iteration set initially. After the
+ iterations are done, internal iteration counter is 0. If you need to
+ perform another set of iterations, you need to set the number of
+ iterations again. <BR><B>Note: </B>Tasks which performed all their
+ iterations remain active.
+ </P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">aCallback is a
+ pointer to a void function without parameters</P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">aScheduler –
+ <B>optional</B> reference to existing scheduler. If supplied (not
+ NULL) this task will be appended to the task chain of the current
+ scheduler). <B>Default=NULL</B></P>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">aEnable –
+ <B>optional</B>. Value of <B>true </B>will create task enabled.
+ <B>Default = false</B></P>
+</OL>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">All
+tasks are created <B>disabled</B> by default (unless aEnable = true).
+You have to explicitly enable the task for execution.</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Enabled
+task is scheduled for execution immediately. Enable tasks with delay
+(standard execution interval or specific execution interval) in order
+to defer first run of the task.</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>INFORMATION</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">The
+following 3 “getter” functions return task status
+(enabled/disabled), execution interval in milliseconds, number of
+<I><B>remaining</B></I> iterations.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>bool
+isEnabled() </B>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>unsigned
+long getInterval()</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>long
+getIterations() </B>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>long getOverrun()</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">If
+library is compiled with <FONT FACE="Courier New, monospace">_TASK_TIMECRITICAL</FONT>
+enabled, tasks are monitored for “long running” scenario. A “long
+running” task is a task that does not finish processing its
+callback functions quickly, and thus creates a situation for itself
+and other tasks where they don't run on a scheduled interval, but
+rather “catch up” and are behind. When task scheduler sets the
+next execution target time, it adds Task's execution interval to the
+previously scheduled execution time:</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"> <B>next
+execution time = previous execution time + task execution interval</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">If
+<B>next execution time</B> happens to be already in the past (<B>next
+execution time</B> &lt; <B>millis()</B>), then task is considered
+<I><B>overrun</B></I>. <B>GetOverrun</B> function returns number of
+milliseconds between next execution time and current time. If the
+<B>value is negative</B>, the task is overrun by that many
+milliseconds.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Positive
+value indicate number of milliseconds of slack this task has for
+execution purposes.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>bool
+isFirstIteration()</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>bool
+isLastIteration()</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">For
+tasks with a defined number of iterations, indicates whether current
+pass is a first or a last iteration of the task (respectively).
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in; page-break-after: avoid">
+<B>CONTROL:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void enable();</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Enables
+the task, and schedules it for immediate execution (without delay) at
+this or next scheduling pass depending on when the task was enabled.
+Scheduler will execute the next pass without any delay because there
+is a task which was enabled and requires execution.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void delay();</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Schedules
+the task for execution after a delay (aInterval), but does not change
+the enabled/disabled status of the task.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void
+enableDelayed();</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Enables
+the task, and schedules it for execution after a delay (aInterval).
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void enableDelayed
+(unsigned long aDelay);</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Enables
+the task, and schedules it for execution after a specific delay
+(aDelay, which maybe different from aInterval).
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void restart();</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">For
+tasks with limited number of iterations only, <B>restart</B> function
+will re-enable the task, set the number of iterations back to when
+the task was created and and schedule the task for execution as soon
+as possible.</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void restartDelayed
+(unsigned long aDelay);</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Same
+as <B>restart() </B>function, with the only difference being that
+Task is scheduled to run first iteration after a delay = <B>aDelay</B>
+milliseconds.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void disable();</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Disables
+the task. Scheduler will not execute this task any longer, even if it
+remains in the chain. Task can be later re-enabled for execution.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void set(unsigned
+long aInterval, long aIterations, void (*aCallback)());</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Allows
+dynamic control of all task execution parameters in one function
+call.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Next three “setter”
+functions allow changes of individual task execution control
+parameters.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>void
+setInterval (unsigned long aInterval) </B>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>void
+setIterations (long aIterations) </B>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>void
+setCallback (void (*aCallback)()) </B>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Note: </B>Next
+execution time calculation takes place <B>after</B> the callback
+function is called, so new interval will be used immediately by the
+scheduler. For the situations when one task is changing the interval
+parameter for the other, <B>setInterval</B> function calls <B>delay
+</B>explicitly to guarantee schedule change, however it <B>does not
+</B>enable the task if task is disabled.</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Note: </B><SPAN STYLE="font-weight: normal">Tasks
+that ran through all their allocated iterations are disabled.
+</SPAN><B>SetIterations()</B><SPAN STYLE="font-weight: normal">
+method </SPAN><B>DOES NOT</B><SPAN STYLE="font-weight: normal">
+enable the task. Either enable explicitly, or use restart methods. </SPAN>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>TASK SCHEDULER:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>CREATION:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>Scheduler()</B><BR><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Default
+constructor.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Takes
+no parameters. Creates task scheduler with default parameters and an
+empty task queue.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void init()</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Initializes
+the task queue and scheduler parameters, Executed as part of
+constructor, so don't need to be explicitly called after creation.</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>Note:
+</B>be default (if compiled with <FONT FACE="Courier New, monospace">_TASK_TIMECRITICAL</FONT>
+enabled) scheduler is allowed to put processor to IDLE sleep mode. If
+this behavior was changed via <B>allowSleep() </B>function, <B>inti()
+</B>will <B>NOT</B> reset allow sleep particular parameter.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR><B>void
+addTask(Task&amp; aTask)</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Adds
+task aTask to the execution queue (or chain) of tasks by appending it
+to the end of the chain. If two tasks are scheduled for execution,
+the sequence will match the order tasks are appended to the chain.
+However, in reality, due to different timing of task execution, the
+actual order will be different.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>Note:
+</B>Currently, changing the execution dynamically is not supported.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">If
+you need to reorder the queue – initialize the scheduler and re-add
+the tasks in a different order.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR><B>void
+deleteTask(Task&amp; aTask)</B></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Deletes
+task aTask from the execution chain. The chain of remaining tasks is
+linked together (i.e</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">if
+original task chain is 1 → 2 → 3 → 4, deleting 3 will result in
+1 → 2 → 4).</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><B>Note:
+</B>it is not required to delete a task from the chain. A disabled
+task will not be executed anyway, but you save a few microseconds per
+scheduling pass by deleting it, since it is not even considered for
+execution.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">An
+example of proper use of this function would be running some sort of
+<B>initialize</B> task in the chain, and then deleting it from the
+chain since it only needs to run once.
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void allowSleep(bool
+aState) </B>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Available
+in API only if compiled with <FONT FACE="Courier New, monospace">_TASK_TIMECRITICAL</FONT>
+enabled. Controls whether scheduler is allowed (<B>aState =true</B>),
+or not (<B>aState =false</B>) to put processor into IDLE sleep mode
+in case not tasks are scheduled to run.</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">The
+<B>default</B> behavior of scheduler upon creation is to allow sleep
+mode.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR><B>void enableAll()</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><B>void disableAll()</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">enables
+and disables (respectively) all tasks in the chain. Convenient if
+your need to enable/disable majority of the tasks (i.e. disable all
+and then enable one).
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR><B>Task&amp;
+currentTask()<BR></B><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Returns
+reference to the task, currently executing via <B>execute()</B> loop.
+Could be used by callback functions to identify which of the
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR><B>void execute()</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">Executes
+one scheduling pass, including end-of-pass sleep. This function
+typically placed inside the <B>loop()</B> function of the sketch.
+Since <B>execute</B> exits after every pass, you can put additional
+statements after <B>execute</B> inside the <B>loop()</B>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in; page-break-after: avoid">
+<B>IMPLEMENTATION SCENARIOS AND IDEAS:</B></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<OL>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in"><B>EVENT DRIVEN
+ PROGRAMMING</B></P>
+</OL>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Each of the processes
+of your application becomes a separate and distinct programming area,
+which may or may not interact and control each other.
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Example:
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">In a plant watering
+system you need to measure soil humidity, control pump and display
+the results</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Each of the areas
+becomes a task:</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>Task
+<B>tMeasure</B> (TMEASURE_INTERVAL*SECOND, -1,
+&amp;measureCallback);<BR>Task <B>tWater</B>
+(TWATER_INTERVAL*SECOND, RETRIES, &amp;waterCallback);<BR>Task
+<B>tDisplay</B> (TDISPLAY_INTERVAL*SECOND, -1, &amp;displayCallback);
+<BR></FONT></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>Scheduler
+</FONT></FONT><FONT FACE="Courier New, monospace"><FONT SIZE=2><B>taskManager</B></FONT></FONT><FONT FACE="Courier New, monospace"><FONT SIZE=2>;</FONT></FONT><BR><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Further, once you turn
+on the pump, you keep it running for TWATER_INTERVAL interval and
+then turn it off. Turning off a pump is also a task which only needs
+to run once for every time the pump is turned on:</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>Task
+</FONT></FONT><FONT FACE="Courier New, monospace"><FONT SIZE=2><B>tWaterOff</B></FONT></FONT><FONT FACE="Courier New, monospace"><FONT SIZE=2>
+(WATERTIME*SECOND, 1,</FONT></FONT><FONT FACE="Courier New, monospace">
+&amp;waterOffCallback);</FONT><BR><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in">Example of the callback
+function:</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>void
+waterOffCallback() {<BR> motorOff();<BR>
+tWater.enableDelayed();<BR>}</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>or</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>void
+waterCallback() {<BR> if (tWater.getIterations()) {</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>//
+If this is not the last iteration = turn the pump on<BR>
+motorOn();<BR> tWaterOff.set(parameters.watertime * SECOND, 1,
+&amp;waterOffCallback);<BR> tWaterOff.enableDelayed();<BR>
+return;<BR> }</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>//
+We could not reach target humidity – something is wrong<BR>
+motorOff;<BR> taskManager.disableAll();<BR> tError.enable();<BR>}</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Your
+sample <B>setup</B>() and <B>loop</B>() (partially) are as follows. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif"><B>Note:
+</B>please note that tWater is <B>not</B> activated during setup().
+It is activated by tMeasure callback once the watering conditions are
+met. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif"> </FONT><FONT FACE="Courier New, monospace">setup()</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Courier New, monospace">
+ ...</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">
+<FONT FACE="Courier New, monospace">tWater.setIterations(parameters.retries);<BR>
+ tWaterOff.setInterval(parameters.watertime * SECOND);<BR><BR><BR>
+taskManager.init();<BR> taskManager.addTask(tMeasure);<BR>
+taskManager.addTask(tDisplay);<BR> taskManager.addTask(tWater);<BR>
+taskManager.addTask(tWaterOff);<BR> <BR> tMeasure.enable();<BR>
+tDisplay.enable();<BR><BR> currentHumidity =
+measureHumidity();<BR>}<BR><BR><BR>void loop ()<BR>{<BR>
+taskManager.execute();<BR>}</FONT><FONT FACE="Times New Roman, serif"><BR></FONT><BR>
+</P>
+<OL START=2>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in">“<FONT FACE="Times New Roman, serif"><B>NATIVE”
+ SUPPORT FOR FINITE STATE MACHINE</B></FONT></P>
+</OL>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Define
+“states” as callback function or functions. Each callback
+function executes activities specific to a “state” and then
+“transitions” to the next state by assigning next callback
+function to the task. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Transition
+from one state to the next is achieved by setting next callback
+function at the end of preceding one. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif"><B>Note:
+</B>do not call the next callback function. Let the schedule take
+care of that during the next pass. (Thus letting other tasks run). </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Example:
+Blinking LED 2 times a second could be achieved this way</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">Task
+tLedBlinker (500, -1, &amp;ledOnCallback);</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">Scheduler
+taskManager;</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">void
+ ledOnCallback() {</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> turnLedOn();</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> tLedBlinker.setCallback(&amp;ledOffCallback);</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">}</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">void
+ ledOffCallback() {</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> turnLedOff();</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> tLedBlinker.setCallback(&amp;ledOnCallback);</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">}</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">setup()
+{</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> taskManager.init();<BR>
+ taskManager.addTask(tLedBlinker);</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> </FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> tLedBlinker.enable();</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">}</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">loop
+() {</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"> taskManager.execute();</FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace">}</FONT><FONT FACE="Times New Roman, serif"><BR></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Obviously
+the example is simple, but gives the idea of how the tasks could be
+used to go through states.</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<OL START=3>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif"><B>MULTIPLE
+ POSSIBLE CALLBACKS FOR TASK</B></FONT></P>
+</OL>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">There
+may be a need to select an option for callback function based on
+certain criteria, or randomly. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">You
+can achieve that by defining an array of callback function pointers
+and selecting one based on the criteria you need. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Example:
+when a robot detects an obstacle, it may go left, right backwards,
+etc. Each of the “directions” or “behaviors” are represented
+by a different callback function. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">Another
+example of using multiple callbacks:</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">You
+may need to “initialize” variables for a particular task.</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">In
+this case, define a tasks with two callbacks:</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>Task
+<B>tWork</B> (T_INTERVAL, -1, &amp;workCallbackInit);</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">…</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>void
+ workCallbackInit() {</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> //
+do your initializationstuff here</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> </FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> //
+finally assigne the main callback function </FONT></FONT>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> tWork.setCallback(&amp;workCallback);</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>}</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>void
+workCallback() {</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> //
+main callback function</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> …</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>}</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">The
+task will initialize during first execution pass and switch to
+“regular” callback execution starting with second pass. There is
+a delay between first and second passes of the task (scheduling
+period, if defined). In order to execute the second pass immediately
+after initialization first pass, change the above code like this:</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>void
+ workCallbackInit() {</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> //
+do your initializationstuff here</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> </FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> //
+finally assigne the main callback function </FONT></FONT>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> tWork.setCallback(&amp;workCallback);</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2> tWork.enable();</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>}</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">The
+task will run initialization first, then immediately second pass, and
+then switch to processing at regular intervals starting with a third
+pass. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<OL START=3>
+ <LI><P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif"><B>INTERRUP-DRIVEN
+ EXECUTION SUPPORT </B></FONT>
+ </P>
+</OL>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif">In
+case of interrupt-driven program flow, tasks could be scheduled to
+run once to request asynchronous execution (request), and then
+re-enabled (restarted) again with a different callback function to
+process the results. </FONT>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><FONT FACE="Times New Roman, serif"><B>Example</B>:
+event driven distance calculation for ultrasonic pulses. EchoPin #6
+triggers pin change interrupts on rising and falling edges to
+determine the length of ultrasonic pulse.</FONT></P>
+<P CLASS="western" STYLE="margin-bottom: 0in"><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>#include
+&lt;DirectIO.h&gt;<BR>#include &lt;TaskScheduler.h&gt;<BR>#include
+&lt;PinChangeInt.h&gt;<BR><BR><BR>#define TRIGGERPIN 5<BR>#define
+ECHOPIN 6<BR><BR>Output&lt;TRIGGERPIN&gt;
+pTrigger;<BR>Input&lt;ECHOPIN&gt; pEcho;<BR><BR>Scheduler
+r;<BR><BR>Task tMeasure(1000, -1, &amp;measureCallback);<BR>Task
+tDisplay(1000, -1, &amp;displayCallback);<BR>Task tPing(0, 1,
+&amp;pingCalcCallback);<BR><BR><BR>volatile bool pulseBusy =
+false;<BR>volatile bool pulseTimeout = false;<BR>volatile unsigned
+long pulseStart = 0;<BR>volatile unsigned long pulseStop =
+0;<BR>volatile unsigned long pingDistance = 0;<BR><BR><BR>void
+pingTrigger(unsigned long aTimeout) {<BR> if (pulseBusy) return; //
+do not trigger if in the middle of a pulse<BR> if (pEcho == HIGH)
+return; // do not trigger if ECHO pin is high<BR> <BR> pulseBusy =
+true;<BR> pulseTimeout = false;</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2><BR>
+ pTrigger = LOW;<BR> delayMicroseconds(4);<BR> pTrigger = HIGH;<BR><BR>
+ tPing.setInterval (aTimeout);<BR><BR> delayMicroseconds(10);<BR>
+pTrigger = LOW; <BR></FONT></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">
+<FONT FACE="Courier New, monospace"><FONT SIZE=2>tPing.restartDelayed();
+// timeout countdown starts now<BR></FONT></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>//
+will start the pulse clock on the rising edge of ECHO pin</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">
+<FONT FACE="Courier New, monospace"><FONT SIZE=2>PCintPort::attachInterrupt(ECHOPIN,
+&amp;pingStartClock, RISING); <BR>}<BR><BR></FONT></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>//
+Start clock on the <B>rising</B> edge of the ultrasonic pulse<BR>void
+pingStartClock() {<BR> pulseStart = micros();<BR>
+PCintPort::detachInterrupt(ECHOPIN); // not sure this is necessary<BR>
+ PCintPort::attachInterrupt(ECHOPIN, &amp;pingStopClock, FALLING); <BR>
+ tPing.restartDelayed();<BR>}<BR><BR>// Stop clock on the <B>falling</B>
+edge of the ultrasonic pulse<BR>void pingStopClock() {<BR> pulseStop
+= micros();<BR> PcintPort::detachInterrupt(ECHOPIN);</FONT></FONT></P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in">
+<FONT FACE="Courier New, monospace"><FONT SIZE=2>pingDistance =
+pulseStop - pulseStart;<BR> pulseBusy = false;<BR> tPing.disable();
+// disable timeout<BR>}<BR></FONT></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>//
+Stop clock because of the timeout – the wave did not return<BR>void
+pingCalcCallback() {<BR> if (pulseBusy) {<BR> pingStopClock();<BR>
+ }<BR> pulseTimeout = true;<BR>}<BR><BR><BR><BR>// Initial measure
+callback sets the trigger<BR>void measureCallback() {<BR> if
+(pulseBusy) { // already measuring, try again<BR>
+tMeasure.enable();<BR> return;<BR> }<BR> pingTrigger(30); // 30
+milliseconds or max range of ~5.1 meters<BR>
+tMeasure.setCallback(&amp;measureCallbackWait);<BR>}<BR></FONT></FONT><BR>
+</P>
+<P CLASS="western" STYLE="margin-left: 0.49in; margin-bottom: 0in"><FONT FACE="Courier New, monospace"><FONT SIZE=2>//
+Wait for the measurement to <BR>void measureCallbackWait() {<BR> if
+(pulseBusy) return;<BR> tMeasure.setCallback(&amp;measureCallback);
+<BR>}<BR><BR><BR>bool state = true;<BR><BR>void displayCallback() {<BR>
+ char d[256];<BR> <BR> unsigned long cm = pingDistance * 17 / 100;
+// cm<BR> <BR> snprintf(d, 256, &quot;pulseStart =
+%8lu\tpulseStop=%8lu\tdistance, cm=%8lu&quot;, pulseStart, pulseStop,
+cm);<BR> Serial.println(d);<BR> <BR>}<BR><BR>void setup() {<BR> //
+put your setup code here, to run once:<BR> <BR>
+Serial.begin(115200);<BR> <BR><BR> pTrigger = LOW;<BR> pEcho =
+LOW;<BR> <BR> r.init();<BR> r.addTask(tDisplay);<BR>
+r.addTask(tMeasure);<BR> r.addTask(tPing);<BR> <BR>
+r.enableAll();<BR> tPing.disable();<BR>}<BR><BR>void loop() {<BR>
+// put your main code here, to run repeatedly:<BR> r.execute();<BR>}<BR></FONT></FONT><BR>
+</P>
+</BODY>
+</HTML> \ No newline at end of file
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