Abstract: Each channel of a priority encoder register is equipped with a latch for storing one bit of a binary data word. The channel of highest priority generates an output which is applied to encoding means which in turn generates a unique code. The channel output is also fed back to reset its associated latch to permit the channel of next highest priority to generate an output.

Abstract: A high speed, low power clocked driver circuit is provided. DC paths from voltage V.sub.DD to ground is eliminated by carefully clocking field effect transistors within the driver circuit. By using bootstrapping techniques, the output of the circuit approaches V.sub.DD. Two of the high speed, low power driver circuits are combined to drive a ratioless output circuit in order to provide an output buffer circuit having a TTL compatible output.

Abstract: A peripheral interface adaptor (PIA) circuit for data processing systems contains memory elements or control registers allowing modification under program control of the logical functions of the PIA.The peripheral interface adaptor includes a plurality of system data bus buffer circuits coupled to a system data bus and further includes peripheral interface buffer circuits coupled to a bidirectional peripheral data bus. The direction of data flow in the peripheral data bus is controlled by a data direction register. Data from the system data bus buffer is entered into an input register, and is transferred from there to an input bus coupled to the control register, a data direction register and a data register. Data from the peripheral data bus, the data direction register and the control register are transferred via an output bus to the system data bus buffers.

Abstract: A carrier correction circuit accepts a serial digital data input stream having an underlying carrier frequency associated with it and generates a corrected carrier signal synchronized with the underlying carrier frequency. The input stream may, for example, be a serial output of an analog-to-digital converter having a differential phase shift keyed analog signal applied to its analog input, the underlying carrier frequency being the carrier frequency of the DPSK signal. The carrier correction circuit includes a phase detector which receives the serial digital data input stream and two representations of the recovered carrier which are shifted in phase from each other by 90.degree.. Each of these representations of the recovered carrier is mixed with the serial digital data input stream by means of first and second mixer circuits, and the results are loaded into first and second serial accumulators, which accumulate, respectively, the average products of the two mixer circuits over a certain time period.

Abstract: A programmable timer module (PTM) is provided as a component of a microprocessor system in order to generate and measure varying time intervals under program control. The programmable timer module includes, in one embodiment, three independent 16-bit timers. Each timer includes a 16-bit counter and a 16-bit latch. The programmable timer module also includes an 8-bit status register and an 8-bit control register each of which may be coupled to an 8-bit bidirectional data bus of a microprocessor system. Selection circuitry is provided which permits the microprocessor to select either the control register or the status register. Information can be written into the control register; the operation is effected by means of read/write circuitry and a read/write input. Any one of the three timers can also be selected by means of the selection circuitry, and a 16-bit number can be written into the selected 16-bit latch.

Abstract: An asynchronously timed digital flip-flop circuit eliminates malfunction occurring when internal race conditions cause the flip-flop to lock up at the guasi-stable threshold state in which both input and output signals of the flip-flop are not at true logic levels but are equal to each other. The addition of special circuitry to reject these "false" outputs eliminates their propagation in the digital system in which said flip-flop is employed.