U23 2007/Evil Solutions/schiebe.c

#include <avr/io.h>

int main(void) {

        DDRA = 0xFF;
	PORTA = 0x00;

	// Set OE @ PORTA3
	PORTA |= (1 << 3);

	uint16_t i;

	uint16_t a;
	uint16_t b;


	for (i = 0 ; i < 16 ; i ++) {

		// Clock @ PORTA2 every 2×
                // on->off->on->off->…
		if ( i % 2 ) {
			PORTA |= (1 << 2 );
		} else {
			PORTA &= ~ (1 << 2 );
		}

		PORTA &= ~ (1<<2);

	}

	// Set Strobe @ PORTA0
	PORTA |= (1 << 0 ) ;
        // Delay
	for (b = 0; b < 0xffff; b++) {
		PORTB &= (1 << 1);
	}
        // Unset Strobe @ PORTA0
	PORTA &= ~ (1 << 0 ) ;

        // Delay
	for (a = 0; a < 5; a++) {
		for (b = 0; b < 0xffff; b++) {
			/* nix */
		}
	}

	for ( i = 0; i < 16 ; i ++) {

/*		// Set Data
		if ( ((int) (i/2)) >= 2 && ((int) (i/2)) <= 5) {
			PORTA &= ~ (1 << 1);
		} else {
			PORTA |=  (1 << 1);
		}
*/		

                // set Data @ PORTA1 every 4×
		if ( ((int) i/2) % 2 ) {
			PORTA |= (1 << 1);
		}else {
			PORTA &= ~ (1 << 1);
		}


		// set Clock @ PORTA2 every 2×
		if ( i % 2 ) {
			PORTA |= (1 << 2 );
		} else {
			PORTA &= ~ (1 << 2 );
		}

		// Set and unset Strobe @ PORTA0
		PORTA |= (1 << 0 ) ;
		PORTA &= ~ (1 << 0 ) ;


		// Set OE @ PORTA3
		PORTA |= (1 << 3);
		
                // Delay
		for (a = 0; a < 5; a++) {
			for (b = 0; b < 0xffff; b++) {
				/* nix */
			}
		}
	}

	return 0;

}