k03asleep.ino

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 //220216
 #include <krnl.h>
 // one task loops and blink
 
 
 // hint using k_sleep instead og k_eat_ticks
 // k_eat_ticks eat your cpu time 
 
 // k_eat_ticks is busy waiting meaning it is using cpu time
 // See in krnl.c approx line 597
 // In contradition k_sleep deactivate the calling task for the time given as parameter
 // and is reactivated (reinserted in the activeQ) after timeout
 
 // ?: how much cputime does t2 used in one loop
 // ?: how much time does t1 use in one loop
 // ?: what will happen if you increase t1 priority to 9 ?
 // ?: why is t2 running in bursts
 // ?: Can you predict the minimum time it takes to k_eat_ticks(2000) if you do not know
 //    what other tasks are doing  (a:no)
 // ?: Can you predict minimu time it takes to k_sleep(2000);   (a: yes)
 
 struct k_t *p1, *p2;
 #define STK 110
 
 unsigned char s1[STK], s2[STK];
 
 void t1()
 {
     int v;
     
     while (1) {
         k_eat_msec(2000);   // burn of cpu time for 2000 ticks
         k_sleep(2000);      // sleep - no cpu eat for 2000 ticks
     }
 }
 
 void t2()
 {
     int i = 0;
     while (1) {
         digitalWrite(13, HIGH);
         k_sleep(50);
         digitalWrite(13, LOW);
         //k_sleep(50);
         //or
         k_eat_msec(50);
     }
     // do we keep up in pace ?
 }
 
 
 void setup()
 {
     int res;
     Serial.begin(115200);
     while (! Serial) ;
     pinMode(13, OUTPUT);
     
     k_init(2, 0, 0); // init with space for one task
     //         |--- no of mg Queues (0)
     //       |----- no of semaphores (0)
     //     |------- no of tasks (2)
     
     // priority low number higher priority than higher number
     p1 = k_crt_task(t1, 10, s1,STK); // t1 as task, priority 9, 100 B stak
     p2 = k_crt_task(t2, 10, s2,STK); // t2 as task, priority 10, 100 B stak
     
     Serial.println("bef start");
     res = k_start(); // 1 milli sec tick speed
     // you will never return from k_start
     Serial.print("ups an error occured: "); Serial.println(res);
     while (1) ;
 }
 
 void loop() {}