A storage element for use in a logic array including a flip-flop device and a complex logic circuit interconnected in such a way that the output of the complex logic circuit is an input to the flip-flop. A Toggle Flip-Flop Control (TFFC) signal, an invert control (INV) signal, and a clock (CLK) signal...http://www.google.de/patents/US4677318?utm_source=gb-gplus-sharePatent US4677318 - Programmable logic storage element for programmable logic devices
