brainstorming with a scheduler.

[seemaxie]

The controller which i am using executes code in terms of tasks (Round- robin fashion). It does not got any main function. for example:

int i ; // getting the i value over serial interface

task1(i==0)
{
  do something;
}

task2(i==1)
{
 do something;
}

Considering the above situation, when i variable gets value 0 over serial interface task1 evaluates to TRUE and it executes again and again before the value changes to 1. When i variable changes to 1 task2 executes again and again before the value changes to 0. My question is, i want these tasks to execute only once but not again n again.

What is precisely mean is

task1(i==0)
do something but next time only if i changes to 1 and back to 0;

PS: the i value can only be 1 or 0 and i can improvise the task's condition. for example: task1(i==0 & something)


Please give your inputs n ideas about solving such problem.

[Shurik]

Maybe:

int i;
int task1done = 0;
int task2done = 0;

while(1) {
   i = getivalue(); // getting the i value over serial interface

   if (i==0 && !task1done)
   {
      task1();
      task1done = 1;
      task2done = 0;
   }
 
   if (i==1 && !task2done)
   {
      task2();
      task2done = 1;
      task1done = 0;
   }
 }

How are you going to interrupt all this process?

[seemaxie]

@shurik thanks a ton . That really works in my case. It actually works this way

int i;
int task1done = 0;
int task2done = 0;
  /* i dont have to use while(1) as controller takes care of looping 
and the value received in the task1 over serial interface is used 
in the execution of rest of tasks. Actually, i am receiving
 over 6 bytes in task1 over SPI and there are over 25 tasks following task1 . */

while(1) {  

  task1(getvalue)   
  {
   i = getvalue;
  }

   task2 (i==0 && !task1done)

   {
      task1();
      task1done = 1;
      task2done = 0;
   }
  
   task3(i==1 && !task2done)

   {
      task2();
      task2done = 1;
      task1done = 0;
   }
 }