Additional device for Espruino to support 8 pins in parallel (for discussion)

Actually I should add that because of jsvIterateCallback, shiftOut supports objects as arguments, for instance a data argument containing extra stuff like {data:0,count:512}.

So with a tiny tweak to jsvIterateCallback your code could actually be written like this:

  shiftData = [];
  me.convertArray = function(){
    // ...
    shiftData = [];
    for(i = 0; i < 16; i++){
      shiftData.push(digitalWrite.bind(null,[Enable,Latch,Latch,D,C,B,A,Enable], 5|i<<3));
      shiftData.push(new Uint8Array(ledBuf.buffer,i*64,64));
    }
    me.scan = shiftOut.bind(null,[R1,G1,B1,R2,G2,B2],{clk:Clock}, shiftData);;
  };

This would be way faster, since it's not actually executing any JS in order to do the entire scan - including toggling the data lines.