Simple programmable logic device

Abstract: A nanoprocessor constructed from intrinsically nanometre-scale building blocks is an essential component for controlling memory, nanosensors and other functions proposed for nanosystems assembled from the bottom up. Important steps towards this goal over the past fifteen years include the realization of simple logic gates with individually assembled semiconductor nanowires and carbon nanotubes, but with only 16 devices or fewer and a single function for each circuit. Recently, logic circuits also have been demonstrated that use two or three elements of a one-dimensional memristor array, although such passive devices without gain are difficult to cascade. These circuits fall short of the requirements for a scalable, multifunctional nanoprocessor owing to challenges in materials, assembly and architecture on the nanoscale. Here we describe the design, fabrication and use of programmable and scalable logic tiles for nanoprocessors that surmount these hurdles. The tiles were built from programmable, non-volatile nanowire transistor arrays. Ge/Si core/shell nanowires coupled to designed dielectric shells yielded single-nanowire, non-volatile field-effect transistors (FETs) with uniform, programmable threshold voltages and the capability to drive cascaded elements. We developed an architecture to integrate the programmable nanowire FETs and define a logic tile consisting of two interconnected arrays with 496 functional configurable FET nodes in an area of ∼960 μm(2). The logic tile was programmed and operated first as a full adder with a maximal voltage gain of ten and input-output voltage matching. Then we showed that the same logic tile can be reprogrammed and used to demonstrate full-subtractor, multiplexer, demultiplexer and clocked D-latch functions. These results represent a significant advance in the complexity and functionality of nanoelectronic circuits built from the bottom up with a tiled architecture that could be cascaded to realize fully integrated nanoprocessors with computing, memory and addressing capabilities.

Abstract: The need for a more-readily usable interface for programmable devices is widely recognized. The present invention relates to programmable sequencing devices, or, more particularly, the remote controls for consumer electronic devices. The present invention provides an enhanced interface for facilitating human input of a desired control sequence in a programmable device by employing specialized visual feedback. The present invention also relates to a new interface and method of interfacing with a programmable device, which is usable as an interface for a programmable video cassette recorder.

Abstract: A programmable logic array integrated circuit has a number of programmable logic modules which are grouped together in a plurality of logic array blocks ("LABs"). The LABs are arranged on the circuit in a two dimensional array. A conductor network is provided for interconnecting any logic module with any other logic module. In addition, adjacent or nearby logic modules are connectable to one another for such special purposes as providing a carry chain between logic modules and/or for connecting two or more modules together to provide more complex logic functions without having to make use of the general interconnection network. Another network of so-called fast or universal conductors is provided for distributing widely used logic signals such as clock and clear signals throughout the circuit. Multiplexers can be used in various ways to reduce the number of programmable interconnections required between signal conductors.

Abstract: A user-configurable circuit architecture includes a two dimensional array of functional circuit modules disposed within a semiconductor substrate. A first interconnect layer disposed above and insulated from the semiconductor substrate contains a plurality of conductors and is used for internal connections within the functional circuit modules. A second interconnect layer disposed above and insulated from the first interconnect layer contains a plurality of segmented tracks of conductors running in a first direction and is used to interconnect functional circuit module inputs and outputs. A third interconnect layer disposed above and insulated from the second interconnect layer contains a plurality of segmented tracks of conductors running in a second direction, some of the segments of conductors forming intersections with ones of the segments of the conductors in the second interconnect layer, and is used to interconnect functional circuit module inputs and outputs to implement the desired applications. A plurality of user-configurable interconnect elements are placed directly between the second and third interconnect layers at the intersections of selected segments of the segmented conductors in the second and third interconnect layers. More user-configurable interconnect elements are located between adjacent segments of the segmented conductors in both the second and third interconnect layers. Pass transistors located in the semiconductor substrate in between the functional circuit modules are connected between adjacent segments in both the second and third interconnect layers and between selected intersecting segments in the second and third interconnect layers.