I just remembered that at least some of the Displaytech displays have their terminals at the lower left of the display. Many displays with the terminals in that location have a non-standard pinout, typically 14, 13 .... 2, 1, 15, 16 instead of 1, 2, .... 15, 16 (reading left to right). Perhaps you have one of those in which case you could be using the data pins in place of the power and control pins.
Don