Developing function millis of arduino

Question

I am looking how to develop function similar of function millis of arduino in ForeC language(is a special language and use same syntax of C). It doesn't support time.h library, so i find this method to develop function millis:

int clock;
int millis(){
while(1){
 clock++;
 return clo
}
}

but when i call this function in this function:

void drive_buzzer()
{

  typedef enum { e_sys_wait_buz, e_play_buz, e_end_buz, e_silence_buz} buz_state_t;
  static unsigned char buz_state = e_sys_wait_buz;
  static unsigned long timer = 0;


 switch ( buz_state ) {
  // Waiting for a sound to emit...
  case e_sys_wait_buz:
    if ( g_snd.snd_evt )
    {
      g_snd.repeat--;
      timer = millis()+g_snd.duration;
      //tone(BUZZER_PIN,g_snd.freq);  
     // pwm(g_snd.freq,0.5);
      printf("%s\n","bbbbbbbbbbbbbbbbbbbbbbbbbbbbeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeepppp" );   
      buz_state = e_play_buz;
      printf("%d\n",millis() );
      printf("%ld\n",timer );
    }
    break;

  // Play the sound
  case e_play_buz:

      if ( millis() > timer ) {
        //noTone(BUZZER_PIN);
        //printf("%s\n","e_play_buz" );   
        buz_state = e_end_buz;
      }
    break;

  // Stop the sound
  case e_end_buz:
    if ( g_snd.repeat != 0 ) { 
        g_snd.repeat--;
        //printf("%s\n","e_end_buz" );  
        timer = millis()+g_snd.interval;
        buz_state = e_silence_buz;
    }
    else
      buz_state = e_sys_wait_buz;
    break;

  // Silence interval between two sounds
  case e_silence_buz:
    if ( millis() > timer ) {
      //tone(BUZZER_PIN,g_snd.freq); 
      //printf("%s\n","e_silence_buz" );   
      timer = millis()+g_snd.duration;
      buz_state = e_play_buz;
    }
    break;
  default:
    break;
 }

}

It works only with the first case :( Any idea or useful links how can i simulate the behavior of clock(without using any library) Thanks!

This while(1){ clock++; return clo } looks awfully like a useless loop. And a syntax error or undefined variable. — Yunnosch
Your millis() simply increments a global variable by 1 and returns it (probably). That has nothing to do with any timing. — datafiddler

Bernhard Bernhard · Accepted Answer · 2020-03-10T11:28:18

You need to implement a timer interrupt which regularly updates your variable clock. Your function millis() then just simply shall return the value of clock. The read of clock from within millis must be atomic.

Developing function millis of arduino

1 Answers