crosswalk.c

// 2010 Kenneth Finnegan
// kennethfinnegan.blogspot.com
//
// Drives cross walk sign in standard cycle
// Outputs buffered through 400V TRIACs
// Runs on standard ATTiny85 with internal oscillator


#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

#define POWER_LINE (0x08)
#define WALK_LATCH (0x10)

// CONSTANTS
#define XTAL		8000000L    // Crystal frequency in Hz

// Wrapper for _delay_ms macro to save flash space
void delay_ms (unsigned int i) {
	unsigned int j;
	for (j=i; j; j--) {
		_delay_ms(1);
	}
}

int main(void)
{
	// Initialize port direction
	DDRB  = POWER_LINE | WALK_LATCH;
	PORTB = 0x00;

	int i;

	while (1) {
		// Latch the walk signal
		PORTB = POWER_LINE | WALK_LATCH;
		delay_ms(500);
		PORTB = POWER_LINE;
		delay_ms(9500);
		// Flash the hand
		for (i=0; i<10; i++) {
			PORTB = 0;
			delay_ms(500);
			PORTB = POWER_LINE;
			delay_ms(500);
		}
		// Hold the hand
		delay_ms(20000);
	}
}