US Patent 7620929 Programmable logic device having a programmable selector circuit

A PLD is configurable to efficiently implement a wide variety of user functions. The PLD includes a programmable interconnect circuit, programmable logic circuits, one-bit registers, selector circuits, and input/output blocks. The programmable interconnect circuit is configurable to connect the signal lines of its output ports to the signal lines of its input ports. The programmable logic circuits are configurable to implement a programmable function generating one-bit signal values from a respective output port of the programmable interconnect circuit. The one-bit registers store a respective one of these one-bit signal values. The programmable selector circuits are each coupled to output ports of a plurality of the one-bit registers, with each of these one-bit registers coupled to a respective one of the programmable logic circuits. The programmable input/output blocks are each coupled to an output port of a respective programmable selector circuit and to a respective input port of the programmable interconnect circuit.