Abstract: A switched capacitor circuit is described which is programmable so that its function can be set by a user. Thus, control circuitry and selection circuitry are provided to enable one of a plurality of alternative control signals to be provided to switch circuits of the switched capacitor circuit. In this way, the function of the switched capacitor circuits can be altered. Where there are a plurality of switched capacitor circuits connected in an array, the topology of the array can be altered by suitably routing particular input signals to particular outputs by selecting the control signals to control the switched circuits. A field programmable array of this type is also described.

Abstract: A programmable logic device comprises a semiconductor with configurable circuitry, an input circuit for encrypted data to determine the configuration of the circuitry, decrypting circuitry responsive to a key value held in a non-volatile data store, and volatile storage circuitry for holding decrypted configuration data. Encrypting circuitry uses the same key value to encrypt configuration data and stores the encrypted configuration data for use in the programmable logic device.

Abstract: A peripheral controller is described which is suitable for connecting a selected one of a plurality of peripheral devices to a computer system. The peripheral controller comprises programmable bidirectional line driver/receiver devices which can be operated in an input only mode, an output only mode or a bidirectional mode and which can be set into an appropriate mode by configuration control data sent from the computer system to the peripheral controller. The peripheral controller also includes a re-configurable logic array which can be configured under the control of the configuration control data to implement a particular interface required for the selected peripheral device. This increases the efficiency of use of a peripheral interface.

Abstract: This invention relates to semiconductor integrated circuits which find utility in analogue systems. An integrated circuit of the invention comprises an array of configurable analogue cells each of which is capable of interconnection with other cells in the array by means of an interconnection network. Each of the cells can be selectively and individually selected by means of select signals and emanating from shift registers. When selected the cell may be configured with configuration data which both sets the cell to take up a particular electrical configuration by means of digital data and sets various programmable resistors and capacitors in the cells to particular values by means of analogue signals. The configuration data is held in a random access memory. Some of this data is converted to analogue form by means of a digital-to-analogue converter.

Abstract: A semiconductor integrated circuit comprising a configurable logic circuit array which may be programmed to configure a plurality of NAND-gates in the array to preform various and different logic functions. An additional logic circuit is provided at each discrete site or cell, and is controllable to cause the additional logic circuit and the logic circuit to implement either a simple NAND logic function or a simple LATCH logic function.

Abstract: Configurable semiconductor integrated circuits as-made each have a plurality of logic circuits formed at discrete sites. For each logic circuit, direct selectably conducting/non-conducting connection paths extend from its output to input of a first set of other logic circuits and to its inputs from outputs of a second set of other logic circuits. All of the sets for all of the logic circuits are each different. Other direct connection paths are selectably connectable to inputs and outputs of the logic circuits. Selection can be irreversible or reversible and involves coincident signal addressing of the sites and coded configuring of the paths at that site. Reversible selection can be via field effect transistors or bipolar transistors and can be at or near normal logic signal levels and speeds. Versatile configurable input/output arrangements are described also reconfigurable data processing systems using the reversible transistor provisions.

Abstract: A gated binary signal transmission circuit in a field effect semiconductor chip comprises a single signal-pass transistor connected between a bit signal input to one of its electrodes and a bit signal output from another of its electrodes. Its control electrode is connected for temporary energizations by switching circuitry operative only at prescribed intervals, the single signal-pass transistor being operative to pass signals between such energizations of its control electrode. Conduction of the single-pass transistor between energizations will persist, though with some decay, due to inherent capacitance and the control electrode being left "floating" between energizations.

Abstract: Selectable signal connection provisions are made for passing signals relative to logic circuitry of digital bipolar semiconductor integrated circuits. Each such provision has formed on the chip for each selectable signal connection, an active circuit element whose conduction state relative to signals concerned is controlled by applied circuit conditions. The conditions are selected by operative control circuitry responsive to a configuring or selection signal applied temporarily thereto for switching between stable states and thus determining the conduction state of the active circuit element.