Honeywell Information Systems Inc.

Homer Warner Miller

James L King

Steven L Crain

An apparatus for storing information contained in a selected digital data signal comprises a selector. A first input terminal receives an operational digital data signal when the apparatus is operating in a normal mode, a second input terminal receives a shifted test data signal when the apparatus is operating in a maintenance mode, and a third input terminal is operatively connected to a signal having a constant reset state. The selector operatively connects one of the first, second, and third input terminals to the output terminal of the selector in response to a first and second control signal. A storage element, having a clock input terminal adapted to receive a clock signal and having a reset terminal adapted to receive a reset signal, stores the state present at the selected input terminal of the selector coincident with the clock signal. A switching element couples the second control signal to the reset terminal of the storage element when the apparatus is in the normal mode thereby causing the apparatus to be placed in a rest state immediately upon the occurrence of the second control signal asynchronously to the clock signal, and couples the second control signal to the selector in the maintenance mode thereby causing the third input terminal of the selector to be operatively connected to the output terminal of the selector causing the apparatus to be placed in the reset state coincident with the clock signal, the second control signal having priority over the first control signal in the selection of the input terminals of the selector.

Apparatus providing improved diagnosability

A test and maintenance system for use with a data processing system comprising a specialized circuit set wherein the circuit set registers can be configured into a serial array, a clock signal distribution system capable of delivering controlled clock signals to selected serial arrays, a maintenance data processor for providing predetermined signal groups, and addressing apparatus responsive to the predetermined signal groups for loading and unloading register arrays in response to the predetermined signals. The disclosed apparatus permits a predetermined signal group to be entered into the serial register array, a predetermined number of clock cycles (i.e. series of operations performed on the data), and the resulting signals shifted from the serial register array and signals applies to data processing unit for display or analysis. By comparing the expected result for a given initial state with the actual result of an operation sequence, the accuracy of the operation of a data processing system, or any portion thereof, can be established.

Test and maintenance method and apparatus for a data processing system

A 5-bit D-type master/slave counter/shift register with buffered outputs is disclosed. The counter implements the load, count up, count down, and reset functions and also has the capability to be reconfigured into an inverting serial shift register for Non-Functional Test (NFT) techniques. In addition, the fifth bit may optionally be removed from the counter logic and used as a parity bit, although it will be necessary to use some external logic to implement this parity function.

5-Bit counter/shift register utilizing current mode logic

An arithmetic logic unit employing soft-saturating current mode logic gates receives as inputs two 5-bit bytes and generates a 5-bit binary output byte in accordance with the particular operational mode prescribed by a mode control signal. The unit performs sixteen binary arithmetic or sixteen Boolean logic operations on two 5-bit input fields Ai and Bi. A carry-in input CIN, a carry generate output G, and a carry propogate output P are provided so that the device can be utilized in a full carry look-ahead configuration with a separate carry look-ahead array. A special output F= is provided for zero detection purposes. In addition to the arithmetic or logic operations, the unit generates a parity of the half-sums signal HS, a parity of the half-parities signal HP, a parity of the carries signal PC, and a carry error signal CE. A carry-out signal COUT is also generated.

Current mode 5-bit arithmetic logic unit with parity

A current mode arithmetic logic circuit utilizes a unique combination of a 4-bit and a 5-bit arithmetic logic unit for performing parity prediction and parity checking on an n-bit byte plus parity, in addition to performing 16 binary or 16 Boolean operations on two n-bit plus parity bytes.

Current mode arithmetic logic circuit with parity prediction and checking

An arithmetic logic unit employing soft-saturating current mode logic gates receives as inputs two 4-bit plus parity bytes and generates a 4-bit plus parity binary output byte in accordance with the particular operational mode prescribed by a binary operation mode control signal. The unit performs sixteen binary arithmetic or sixteen Boolean logic operations on two 4-bit plus parity input fields Ai and Bi. A carry-in input CIN, a carry generate output G, and a carry propogate output P are provided so that the device can be utilized in a full carry look-ahead configuration with a separate carry look-ahead array. A special output F=O is provided for zero detection purposes. In addition to the arithmetic and logic operations, the unit performs parity checking, parity carry, and parity prediction operations on the 4-bit plus parity binary input signals, and accordingly special inputs in the form of a carry-in duplicate CID, parity of the half-sums HS, a parity of the half-parities HP, parity of the carries PC, carry error CE, and parity checking command PCK are provided. A special output E indicates a carry or half-sum parity error. A carry-out signal COUT is also provided. The device can be configured to operate on bytes having fewer than four data bits by means of a pair of configuration select signals P1 and P2.

Current mode 4-bit arithmetic logic unit with parity

An improved binary/binary coded decimal arithmetic logic unit employing soft-saturating current mode logic gates operates on pure binary data or binary coded decimal (BCD) data. The unit performs 16 binary and 2 decimal arithmetic operations and 16 Boolean operations on two 4-bit plus parity input fields. The particular operation is determined by a 5-bit mode control signal. A carry-in input CIN, duplicate carry-in input CIND, parity check PCK input, invert parity input IP, decimal mode signal D, and decimal add input DA are also provided. The device generates a binary output resultant of the operation defined by the mode control signal. In addition to the arithmetic or logic operations, the unit performs parity checking, parity carry, and parity prediction operations on 4-bit plus parity binary and BCD fields.

Current mode binary/BCD arithmetic logic unit with parity

A multiple-generating register generates one of several possible multiples of a binary number which is input thereto depending upon the informational content of a 3-bit control signal. For each data stage there exists a data selector circuit, a master/slave circuit, and an output buffer circuit. The device can be configured as an inverting shift register for test and diagnostic purposes. The device is implemented in current mode logic, and a portion of the circuitry operates on differential level signals for increased operational speed and efficiency.

Current mode multiple-generating register

An arithmetic logic array employing soft-saturating current mode logic gates operates on pure binary data or binary coded decimal data. Two 4-bit data inputs are received along with a 5-bit Op code, a carry input, and decimal arithmetic operation signals. In response to a decimal add (DA) one data input is increased by a count of six, and in response to either a BCD add or a BCD subtract (DA + DS) the output is decreased by a count of six if no carry output is generated.

Current mode binary/BCD arithmetic array

A magnitude comparison circuit compares two X-bit binary numbers and two Y-bit binary numbers when a mode control signal is in a first condition and generates outputs indicating the relative magnitudes of the X-bit binary numbers and the Y-bit binary numbers. The magnitude comparison circuit compares two Z-bit binary numbers when the mode control signal is in a second condition and generates an output indicating the relative magnitude of the Z-bit binary numbers, where Z equals the sum of X and Y.

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Peoria, AZ, United States of America

Homer Warner Miller