Attiny13A + MM5481N LED driver?

Using Arduino Microcontrollers
5

LOL thanks for the catch. That was stupid of me :frowning:
Now its working "better" but still not right.
I changed the code as follows:

#define F_CPU 128000
#include <util/delay.h>
#include <avr/io.h>
#include <inttypes.h>
#define SCK _BV(PB4)
void shreg(uint16_t a){
	int z;
	//Start sequence ?
	PORTB = 0; // All pins low
	_delay_ms(1);
	PORTB |= SCK; //SCK high
	_delay_ms(1);
	PORTB &= ~SCK; //SCK low
	_delay_ms(1);
	PORTB |= _BV(PB3); //Serial data high
	_delay_ms(1);
	PORTB |= SCK; //Sck high
	_delay_ms(1);
	PORTB &= ~SCK; //SCK LOW
	_delay_ms(1); 
	for(z = 0;z<35;z++){
		if(z < 14){
			PORTB = (_BV(PB3) * (a&1)); //Output bit if < 14
			a>>=1;
		} else {
			PORTB = 0; //Otherwise output nothing
		}
		_delay_ms(1);
		PORTB |= _BV(PB4); //SCK high
		_delay_ms(1);
		PORTB &= ~_BV(PB4); //SCK low
		_delay_ms(1);
	/*	PORTB = 0; //All pins off
		_delay_ms(1);*/
	}
	
}
int main(){
		unsigned int cat = 0;
		DDRB = _BV(PB3) | _BV(PB4);
		PORTB = 0;
		while(1){
			shreg(0xFFFF);
			_delay_ms(500);
		}
	}

With shreg(0xFF), it correctly lights all LEDS and shreg(0) turns them all off.
The problem is, shreg(1) or shreg(2) does not light the first or second LED.