Abstract: A TTL gate (22) includes a current generating circuit (24) comprising an NPN transistor (30) having its base coupled to a diode (24) and its emitter coupled to one of the gate's output transistors (14). Transistor (30) enables diode (24) to deliver a high current of short duration to the output OUT responsive to a low-to-high output transition. The current provides low-to-high output transition while protecting output transistor (14) from damaging currents caused by a short circuit at output OUT.

Abstract: A floating point processor (10) is provided having a multiplier (48) and an ALU (54) for performing arithmetic calculations simultaneously. The output of the multiplier (48) and ALU (54) are stored in a product register (64) and a sum register (66), respectively. Multiplexers (40,42,44,46) are provided at the inputs to the multiplier (48) and the ALU (54). The multiplexers choose between data in input registers (32,34), product and sum registers (64,66), and an output register (76). Since the multiplier (48) and ALU (54) operate simultaneously, and since the outputs of the multiplier (48) and ALU (54) are available to the multiplexers (40-46), product of sums calculations and sum of products calculations may be performed rapidly. An input stage (12) uses a temporary register (18) to store data from a data bus on the first clock edge, and configuration logic (28) for directing data from the data bus and the temporary register (18) to the input registers (32,34) on a second clock edge.

Abstract: A digital crossbar switch for switching data from an input/output data bus to an internal data bus and to the same or another input/output data bus which includes a plurality of multiplexer logic units, an m-bit internal data bus coupled to each of said multiplexer logic units where m is an integer, and a plurality of n-bit input/output data buses one connected to each of the multiplexer logic units were n is an integer. The switch further includes an m/n to 1 multiplexer, where m/n is an integer, in each multiplexer logic unit. The m/n to 1 multiplexer has an input control to the internal data bus and an output coupled to a corresponding one of the input/output data buses and is operative in response to a configuration control signal to switch a selected n-bits of data from the internal data bus to the corresponding input/output data bus. A memory storage for storing configuration control signals is coupled to the m/n to 1 multiplexer.

Abstract: A microsequencer includes a memory array (110) which is interfaced with a push/pop register (100). Data is input to the push/pop register (100) through a multiplexer (104) and also to Read register (102). The stack comprised of the RAM (110) and the register (100) can be push or pop with control logic (120). Stack pointer (130) and Read pointer (134) are provided for storing the stack and read pointers. The Read register (102) allows reading of data independent of the contents of the push/pop register (100) and the Read pointer (134) allows independent reading of information in the RAM (110).

Abstract: A bit slice processor system includes a bit slice ALU that is cascadable to provide multiple length words. Each of the ALUs provides both command outputs and status outputs. The status outputs are interfaced with each of the package as are the command outputs. Each of the ALUs in the cascaded ALU are controlled by an instruction word to perform a predetermined processing function. Internal status information is processed to generate a command output and a status output. This command is transmitted simultaneously with the status to the remaining packages in the cascaded array to provide processing control.

Abstract: A test circuit for a VLSI integrated circuit includes interface test circuits (20) which are disposed between a logic circuit (16) an output terminal (14). The interface circuits (20) are each operable to provide a transparent interface between logic circuit (16) and output terminals (14) or force a high logic state on the output, a low logic state on the output or a floating state. A test code circuit (22) is operable to receive two logic signals from pins (24) and (26) external to the IC and determine the state of the test interface circuit (20) such that all test interface circuits (20) operate simultaneously in the same mode.

Abstract: An improved 6-input adder is disclosed. The adder decodes pairs of inputs to provide three sets of NAND, NOR and Exclusive OR terms which are inputted to AND-OR-INVERT arrays which generate first and second carry output terms of a 3-bit binary number in less than three gate delays.