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CODE: Selecteer alles

#include <avr/io.h>
#define F_CPU 1000000UL
#include <util/delay.h>

int main(void) {
	
	DDRB |= ( 1 << 4 );
	while (1) {
		PORTB &= ~(1 << 4 );
		_delay_ms(1000);
		PORTB |= ( 1 << 4 );
		_delay_ms(1000);
	}
	return 0;
}

CODE: Selecteer alles

int set_PORTB_bit(int position, int value)
{
        // Sets or clears the bit in position 'position' 
        // either high or low (1 or 0) to match 'value'.
        // Leaves all other bits in PORTB unchanged.
        
        if (value == 0)
        {
                PORTB &= ~(1 << position);      // Set bit # 'position' low
        }
        else
        {
                PORTB |= (1 << position);       // Set bit # 'position' high
        }
        return 1;
}

CODE: Selecteer alles

/*
 * ATtiny13 driving two 74HC595 shift registers
 *
 * Randomly turns on/off output pins of the shift
 * register ICs.
 * A random number of outputs are set high, then
 * a random time delay occurs.  Then the cycle
 *  repeats.
 *
 */
#define F_CPU 1200000UL
#include <stdlib.h>
#include <avr/io.h>
#include <util/delay.h>

#define DATA PB0
#define CLOCK PB1
#define LATCH PB2

int main(void) {
  int d;
  char n;
  char i;

  // set DATA, LATCH and CLOCK pins to OUTPUT
  DDRB |= (1 << DATA);
  DDRB |= (1 << LATCH);
  DDRB |= (1 << CLOCK);
  PORTB = 0;

  while(1) {
    // choose number of LEDs to light up.
    // n will be between 4 and 16
    n = 4 + (random() % 13);

    for(i=0;i<15;i++) {
      // for each LED, probability of it being lit
      // is n/15
      if ((random() % 15) <= n) {
	PORTB |= (1 << DATA);  // set DATA pin high
      } else {
	PORTB &= ~(1 << DATA); // set DATA pin low
      }

      // toggle shift register clock pin
      PORTB |= (1 << CLOCK);
      _delay_ms(2);
      PORTB &= ~(1 << CLOCK);
    }

    // once we've shifted out all 15 values, toggle
    // the latch pin.
    PORTB |= (1 << LATCH);
    _delay_ms(2);
    PORTB &= ~(1 << LATCH);

    // delay random amount of time between
    // 100ms and 500ms
    d = 100 + (random() % 400);
    for(i=0;i<d;i++) {
      // _delay_ms function must be called with a
      // constant value, not a variable!
      _delay_ms(1);
    }

  }
  return 0; // not reached
}