Simple Flashing led program

[crocu]

Hello,


I would like to have a permanent LED flashing program that will flash a led like this :

|||||__|||||__|||||__

5 quick flashes, nothing done during 1 second and 5 quick flashes again ... etc ...

The delay between flashes and hold time has not be very occurate.

Can someone tell me how to do that with a C code ?

Many thanks for your help,

[Sobrietytest]

Code: Select all

void main() {


TRISB = 0x00; // PORTB as ouput
PORTB = 0x00; // Set port output as all 0's

while(1){
for (i=0, i < 5, i++){ //repeat 5 times
    PORTB.F0 = 1;   //switch on LED at PORTB pin 0
    delay_ms(150);  //short delay
    PORTB.F0 = 0;   //switch off LED
    delay_ms(150);
    }

Delay_ms(1000);// 1 second delay
}//endless loop

}

[crocu]

Thank you very much Sobrietytest,

Your code example is fine but i can't delay and have the main loop in hold every 1 second because i need to have other things to be run from there.

If there a way to have led flashing holding 1 second after 5 flashes while the rest of the code is NOT interrupted ?

If so can you show me how to do that please ?

Many thanks,

[drdoug]

I would set up an interrupt timer and for 100 ms (or whatever time) and then count how many times it has been activated. Activate it 5 times to turn on/off and then leave it oftf for 10 counts and then repeat. You just have to keep track of where you are in the count.

[crocu]

Can you show me how to do this please ?

I'm novice this C programming and an example would be much appreciated.

Many thanks,

[drdoug]

I'll try to put something together for you but in the meantime take a look at the mE examples (Flashing LED with Timer 0).

[drdoug]

I put this together while eating my lunch. I did not test or compile so there may be errors and there are more efficient ways of doing things but this should help some.

I modified the mE Timer 0 example. You should be able to do other things in the program but if all depends on what you are doing.

Code: Select all

unsigned cnt, myTick;

void interrupt() {
  if (TMR0IF_bit) {
    cnt++;                 // increment counter
    TMR0IF_bit = 0;        // clear TMR0IF
    TMR0   = 96;
  }
}

void main() {
  OPTION_REG = 0x84;       // Assign prescaler to TMR0
  ANSEL  = 0;              // Configure AN pins as digital
  ANSELH = 0;
  C1ON_bit = 0;            // Disable comparators
  C2ON_bit = 0;
  TRISB = 0;               // PORTB is output
  PORTB = 0xFF;            // Initialize PORTB
  TMR0  = 96;              // Timer0 initial value
  INTCON = 0xA0;           // Enable TMRO interrupt
  cnt = 0;                 // Initialize cnt
  myTick = 0;
  do {
    if (cnt >= 40) {      //  100 ms delay I think
      myTick++;
      cnt = 0;             // Reset cnt
      if (myTick < 10) {     // Flash light 5 times
         PORTB.F0 = ~PORTB.F0
       } // end if (myTick < 10)
      if (myTick >= 10) {    // Leave off for 1 second
         PORTB.F0 = 0;
       if (myTick >= 20) myTick = 0;   // reset myTick to begin cylce again
       }// end if (myTick >= 10)
    }

    // You should be able to add in your other code
    // items here with a minimal impact.
    
  } while(1);
}