Abstract: In a driver circuit, high- and low-impedance drive means (26 and 28 respectively) operate in parallel to effect a desired output transition. Adaptive control means 32 respond to a threshold value of the output signal (VO) and turn off the low-impedance drive means in the course of the output transition. The low initial output impedance of the driver circuit effects rapid charging of a line capacitance CL, while toward the end of the output transition the higher output impedance of the driver circuit more closely matches the input impedance ZL of a load circuit. This higher impedance dampens ringing and thereby reduces induced supply line noise which is conventionally associated with high-speed driver circuits.

Abstract: An input/output (I/O) processor and data processing system in which the processor receives and services interrupt request signals from I/O controllers, which requests may be internally or externally coded, and supervises blockwise transfer of data between an external memory associated with a main processing unit and the I/O controllers. The I/O processor includes an internal memory for storing information pertinent to data transfer from each I/O channel including the address where channel programs, decision tables and data buffers are maintained in external memory. A sequencer executes a specialized instruction set which includes instructions that invoke an interpretation means enabling examination of status registers of the I/O controllers and/or data values therefrom and the branching of execution based thereon.

Abstract: A circuit formed with an input stage (20) and an output stage (22 or 28) uses capacitively enhanced switching to improve switching speed without significantly raising steady-state current utilization. The output stage contains a pair of amplifiers (A1and A2) that respond to complementary signals (V.sub.M1 and V.sub.M2) produced by the input stage. The amplifiers are coupled to a pair of corresponding nodes (N1 and N2). A third amplifier (A3) in the output stage has a control electrode coupled to one of the nodes, a flow electrode coupled to the other node, and another flow electrode coupled to a further node (N3). A current supply (24) provides current at the further node. A charge/discharge element (CD1) produces a capacitive-type charge/discharge action between the further node and a source of a reference voltage (V.sub.R1).

Abstract: A D-type flip-flop arrangement includes first and second latches .Circuitry interposed between the latches blocks any metastable condition that may occur in the first latch from propagating into the second latch. Additionally, the arrangement minimizes the likelihood that the first latch will enter a metastable condition and, if it does, resolves the condition extremely rapidly.