Westinghouse Electric Corporation

Hughes Aircraft Company

Lawrence S Schmitz

Bruce L Troutman

John N Whipple

Warren D Drumheller

Curtis E Dodds

A non-volatile random access memory cell has two branches, each branch comprising a source-to-drain channel and a series load connected to the channel to define a node therebetween, each channel having an associated electron tunneling region, a floating gate overlying the channel and a control gate overlying the floating gate, the control gate of each of the branches connected to the node of the other branch and the floating gate of each of the branches overlying the electron tunneling region of the source-to-drain channel of the other branch. The resulting structure is a cross-coupled floating gate structure in which threshold voltage control of one floating gate tunneling metal oxide semiconductor (FATMOS) transistor is controlled by another FATMOS transistor, the two transistors comprising a single random access memory cell. Data may be written in either volatile or non-volatile mode in a state which is not inverted from that previously stored during volatile writing.

Non-volatile random access memory having non-inverted storage

An LED watch which is capable of displaying both horological information and up to five words of five characters each which are sequentially displayed. These alpha-numeric words are programmed by the watch user.

User programmable alpha-numeric message watch

A system for automatically time setting and message setting or programming of a cased digital watch or a watch module and including both an external setting unit and a serial interface control circuit inside the cased digital watch. The system in accordance with the invention is compatible with either watches that require time setting or watches that require both time setting and message programming and is applicable to any type of manually controllable watch. The time and message set system has a data entry unit that includes a keyboard, a display, a reference time module, a memory, a light source such as a light emitting diode or an LED array as an output and a processor which provides central control of the other functional units. The LED array output supplies coded messages to a light or energy responsive device or phototransistor in position under the face of the watch. The watch includes a novel circuit for responding to the phototransistor and provides time setting and message setting.

Automatic system for setting digital watches

There is described a logic element employing fixed threshold and variable threshold transistors electrically connected together to form a latch. The latch can be made to retain data by keeping certain internal nodes at a high or low voltage level. As such, it acts as an ordinary volatile semiconductor memory latch, whose data can be changed by externally overriding the internal voltage levels of the latch cell. Non-volatile storage capability is achieved by replacing one or several of the transistors in the latch by specially constructed transistors, whose threshold voltage can be raised or lowered upon application of a relatively high voltage pulse between their gate and substrate. By application of such a high voltage pulse, the data stored in the latch can be translated into controlled threshold shifts of the variable threshold transistors, which uniquely represent the initial latch state. Therefore, if power is removed and then returned, the latch will always settle into a state dictated by the final state that existed in the latch before the high voltage pulse was applied. In this way the variable threshold elements of the latch cell make it a non-volatile memory element. Fixed threshold IGFETs, connected so as to bypass the variable threshold elements, enable the latch cell to continue to operate even after a variable threshold element has been rendered irreversibly non-conductive by a high voltage pulse.

Volatile/non-volatile logic latch circuit

A solid state noise generator circuit responds to digital signals indicative of alarm conditions, by initiating frequency modulated digital audio output waveforms distinctly identifying the monitored condition to provide audible recognition of each alarm condition. Each distinct alarm condition results in the application of a different combination of outputs of one multistage counter as preset inputs to a second multistage counter to uniquely frequency modulate the digital square wave input driving the second multistage counter to produce the distinctive frequency modulated digital audio output waveform.

Noise generator circuit for a security system

A solid state security system employing a single 'chip' integrated circuit as the primary electronics located within a compact security console to provide electronic interface with one or more remote monitoring channels including a telephone dialer channel, an annunciator display, a multiplex channel suitable for processing alarm signals from a plurality of security consoles, and an intercom system suitable for providing two-way verbal communication between one or more security consoles and a central control access location.

Solid state security system

In a solid state security system having a plurality of alarm sensors for generating output signals in response to alarm conditions and a corresponding plurality of resettable latching circuits for developing digital output signals indicative of alarm conditions for processing by logic circuits to develop alarm output signals, an automatic test circuit responds to a single activating signal by sequentially supplying simulated alarm condition signals to the respective latching circuits to determine the operational integrity of the latching and logic circuits. At the conclusion of the test sequence the automatic test circuit transmits reset signals to the resettable latching circuits.

Automatic test sequence circuit for a security system

A solid state reset circuit responds to the actuation of a single manual device to both transmit reset signals to the input circuitry associated with fire and intrusion sensors of a security system, and to transmit an arm/disarm signal to the intrusion sensor circuitry if an intrusion alarm condition is present and a fire alarm condition is not present. The use of a single manual device to generate both the reset and arm/disarm signals reduces operator confusion.

Reset circuit for a security system

A security system adapted for monitoring fire, intrusion, and other alarm conditions employs solid state technology to appropriately identify the monitored alarm conditions and initiate appropriate responses. A 'one chip' integrated semiconductor circuit functions as the primary electronics of a master control console to accept both remotely initiated as well as locally initiated input signals and to process the signals and initiate appropriate control and alarm signals. Included on the integrated semiconductor circuit are a digital noise generator circuit, input comparator and latch circuits, system test and reset circuits, and logic circuits for developing digital output signals to both activate monitoring channels and identify the type of alarm condition present.

In a solid state security system, a trouble indicator circuit capable of developing both an audio and visual output signal, by providing a visual indication in the absence of a circuit or component failure and an audio initiating signal in response to the presence of a circuit or component failure.

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Costa Mesa, CA, United States of America

Lawrence S Schmitz