16x4 LCD not displaying anything
The JHD539-164b is a standard KS0066 compatible character LCD. Nearly Identical to the HD44780 controlled lcds, and user end code would be completely compatible.

The difference between a 16x2 LCD and a 16x4 LCD is only that a 16x4 is really a logical 32x2 LCD, address wise.

If you are not getting it to work, double check the wiring, and see if the lcd is not damaged.