k03priorityequal.ino

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//220216
#include <krnl.h>
//
// busy waiting all the way around - like using ya old delay
//
 
// Set t1 priority to  9 == highest priority
// What will happen ? What do you see on the led and the measurements
// REALTIME ?
//
// gives a guess how cpu time is used in krnl "dummy time eating"
 
struct k_t *p1, *p2;
 
#define SS 110
unsigned char s1[SS], s2[SS];
 
 
void t1()
{
    int v;
    
    while (1) {
        k_eat_msec(2000);  // eat time for 2000 ticks so mimic cpu usage == 2000 msec
    }
}
 
unsigned long tStart,tStop;
void t2()
{
    int i = 0;
    while (1) {    
        Serial.println("start");
        tStart = k_millis();
        for (int i=0; i < 10 ; i++) { // 10 loops of 100 milliseconds == 1 second ! ?
            digitalWrite(13, HIGH);
            k_eat_msec(50);
            digitalWrite(13, LOW);
            k_eat_msec(50);
        }
        tStop = k_millis();
        Serial.print((tStop-tStart)/1000.0);
        Serial.print(" sec ");
        Serial.println("Did it take 1 second ???- not - why ");
        // hint task t1 ies eating 50% of cputime
        // the have same priority to you share cpu 50/50
        // so it will approx take 100 msec to execut k_eat_msec(50)
    }
}
 
 
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,SS); // t1 as task, priority 9, 100 B stak
    p2 = k_crt_task(t2, 10, s2,SS); // 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() {}