Diff: Examples/example3.h

Revision:

1:f043501c4bed

Child:

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+/*
+    Copyright (c) 2011 Andy Kirkham
+ 
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+ 
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+ 
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+    
+    @file          example3.h 
+    @purpose       Simple round-robin cooperative scheduler example
+    @date          Mar 2011
+    @author        Andy Kirkham
+*/
+
+/*
+    SimpleScheduler is a cooperative scheduler. What that means is YOU, the
+    programmer MUST cooperate with it. SimpleScheduler will call your task
+    functions based on the schedule you provide. However, it's not a guarenteed
+    scheduled time. It's on a "best effort". However, no tasks are called until
+    the currently executing task completes. What that means is your task function
+    must return before another task can be called.
+    
+    Your tasks therefore should execute as fast as possible and return as soon as
+    they can. But when Mbed's wait API is used you stall your entire system. This
+    example shows how you can wait() in a task without actually waiting at all. In
+    order to do this we use the "Ton" (Timer ON) library. You will need to import
+    this library into your project to use this example:-
+    
+    http://mbed.org/users/AjK/libraries/Ton/latest
+    
+    What follows is basically example1. However, we are going to flash LED1 by 
+    "waiting" 1second in the task. 
+    
+*/
+
+#include "mbed.h"
+#include "SimpleScheduler.h"
+#include "Ton.h"
+
+Ton t1(1000); // Timer ON delay of one second.
+
+DigitalOut led1(LED1);
+DigitalOut led2(LED2);
+DigitalOut led3(LED3);
+DigitalOut led4(LED4);
+
+void f1(SimpleTask *task) {
+    // wait(1); 
+    t1 = Ton::On;
+    if (t1) {
+        led1 = !led1; 
+        t1.reset();
+    }
+}
+void f2(SimpleTask *task) { led2 = !led2; }
+void f3(SimpleTask *task) { led3 = !led3; }
+void f4(SimpleTask *task) { led4 = !led4; }
+
+SimpleScheduler *scheduler;
+
+int main() {
+
+    scheduler = new SimpleScheduler;
+    
+    scheduler
+        ->addTask( new SimpleTask(0,   f1) )
+        ->addTask( new SimpleTask(200, f2) )
+        ->addTask( new SimpleTask(300, f3) )
+        ->addTask( new SimpleTask(0.4, f4) )
+    ;
+    
+    scheduler->run();    
+}
+