Very simple cooperative round-robin task scheduler. See examples.
Examples/example3.h
- Committer:
- AjK
- Date:
- 2011-03-04
- Revision:
- 1:f043501c4bed
- Child:
- 4:49652acb6806
File content as of revision 1:f043501c4bed:
/* 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(); }