So got it working. Needed to ground SO,SD and SI pins.

I have been trying to make LSDj sync for my drum machine project, but so far no luck to make it sync to GB.
I am connecting output port (1-bit) to Game Boy link cable SC via level shifter (3.3v to 5v), connected GND to ground and put SI to 5v as arduino boy seems to do.

Code to send bits is:

  timer tmr;
  unsigned t;
  while(1){
     x <: 0;
        for(ticks=0;ticks<8;ticks++) {
            x <: 1;
            x <: 0;
          }
       tmr :> t;
       // add delay to t, wait until timer reaches that value
      tmr when timerafter (t + PERIOD) :> void;
    }

So sending 8 bits of 1 to port (x), waiting for awhile and doing it again. This should be enough to LSDj to get sync, right?
I can check that individual bits are going to SC port with multimeter if i add lot of delay when sending bit to port.
Still LSDj stays in WAIT state with slave sync mode. Am i missing something crucial here or?