k03priorityequalfixed.ino

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//220216
#include <krnl.h>
//
// sleppy waiting k_sleep("sleeptime in msec");
//
 
// Set t1 priority to  9 == highest priority
// What will happen ? What do you see on the led and the measurements
// REALTIME ?
// change priority of t1 to 9 (higher than  t2) : does it matters ?
 
// gives a guess how cpu time is used in krnl "dummy time eating"
 
struct k_t *p1, *p2;
 
#define SS 140
unsigned char s1[SS], s2[SS];
 
 
void t1()
{
    int v;
    
    while (1) {
        k_sleep(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_sleep(50);
            digitalWrite(13, LOW);
            k_sleep(50);
        }
        
        tStop = k_millis();
        
        Serial.print( (tStop - tStart) / 1000.0);
        Serial.println("  did it take 1 second ?? :-)?");
    }
}
 
// we do sleep instead of busy waiting so others can use cpu
// added breakout so led 13 is ON when dummy task is running
 
 
void setup()
{
    int res;
    Serial.begin(115200);
    while (! Serial) ;
 
    pinMode(13, OUTPUT);
    /* using analyser(like analog discovery) D8 will be dummy running, D9 when first created task is running ,... */
    /* remember to change in k_breakout*/
    /* for (int i=8; i< 14; i++) { pinMode(i,OUTPUT); digitalWrite(i,LOW); } */
    
    
    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() {}
 
 
extern "C" {
    
    void k_breakout() // called every task shift from dispatcher
    {
        
        
        if (pRun->nr == 0)
        {
            PORTB = PORTB | B00100000;  // led13 (bit 5) on let the rest be untouched
        }
        else {
            PORTB = PORTB & B11011111;  // led off uno
        }
    }
    /* using D8-D13 use following instead of teh code above*/
    /* PORTB = (1 << pRun->nr); */
}
 
// on mega led is on portb bit 7 so use B10000000 and B011111111 above