Couldn't Bring MAX7219 under Control to Display 2?

Passing arguments via globals was old-hat in Noah's time.

void clkIn(int x)
{
  for (int i = 15; i>=0; i--)
  {
    digitalWrite(11, bitRead(x, i));  //D15 is shifted first
    //------
    digitalWrite(13, HIGH);//generating clock signal
   // delayMicroseconds(1);
    digitalWrite(13, LOW);
  }

  digitalWrite(8, HIGH);  //LOAD is made High and then Low
  //delayMicroseconds(1);
  digitalWrite(8, LOW);

}

(as were un-named pins)

I have written low level codes which are also not working

You have over 1000 posts, and you think that is an acceptable statement? :o