Hitachi, Ltd.

Keisuke Bekki

Hiroshi Sato

Korefumi Tashiro

Nobuyasu Kanekawa

Shoji Suzuki

Makoto Nohmi

Takayoshi Yokota

Shinya Ohtsuji

Nobuhiro Hamada

Yoshimichi Sato

Seiko Suzuki

Masayoshi Suzuki

Nobuhisa Kobayashi

Hiroyuki Seki

A self-checking circuit, which is useful for a highly reliable system configuration, includes a logic circuit having an error detection function. For function blocks for feeding out a plurality of signals that are at least duplexed, the logic circuit compares the output signals of the function blocks, and detects an error on the basis of results of the comparison. The logic circuit comprises synthesizing means provided to superimpose inherent waveforms assigned in advance to the respective output signals of the function blocks onto the output signals of one of the function blocks. The inherent waveforms are orthogonal waveforms generated by an orthogonal waveform generator circuit. The logic circuit also comprises comparison means for comparing a signal output of the synthesizing means with the signal output of the other function block to detect an error. The whole circuit including the function blocks are judged normal only if the waveforms inherent to both output signals exist.

Logic circuit having error detection function, redundant resource management method, and fault tolerant system using it

Logic circuit having error detection function, redundant resource

A highly reliable display control apparatus and method suitable for use in a computer control system which is required to have high degree of reliability, such as control systems for railroad traffic or a nuclear power station. A meaningful symbol is divided into a plurality of sections and these sections are independently input to either one of the inputs of an interactive man-machine system through different systems so that these sections of the meaningful symbol are displayed in the same frame of the man-machine system, thus enabling the operator to visually detect any abnormality as to whether the displayed meaningful symbol is complete or not, whereby a high degree of reliability of the display is obtained.

Method and apparatus of detecting and displaying abnormal conditions

A self-checking circuit, which is useful for a highly reliable system configuration, includes a logic circuit having an error detection function. For function blocks for feeding out a plurality of signals that are at least duplexed, the logic circuit compares the output signals of the function blocks, and detects an error on the basis of results of the comparison. The logic circuit comprises synthesizing circuitry provided to superimpose inherent waveforms assigned in advance to the respective output signals of the function blocks onto the output signals of one of the function blocks. The inherent waveforms are orthogonal waveforms generated by an orthogonal waveform generator circuit. The logic circuit also compares the output signals having the superimposed inherent waveforms with the signal output of the other function block to detect an error. The whole circuit including the function blocks are judged normal only if the waveforms inherent to both output signals exist.

An air bag operation device which employs only one CPU module to guarantee sufficient fail-safety in the operation of the air bag without increasing the scale of the hardware. A plurality of crash-discriminating programs of different versions and a plurality of self-diagnosing programs of different versions are executed by a single CPU module, a signal is fed to an air bag igniting device based upon a comparison of the discriminated results by the plurality of crash-discriminating programs, and a signal is fed to an abnormality alarm device based upon comparison of the discriminated results of the plurality of self-diagnosing programs.

Air bag operation device

A decoding type select logic generating method includes the steps of listing on a group basis input signal names and output destination signal names contained in register transfer descriptions and control codes for commanding execution of the register transfers for each of the same input signal names and same output destination signal names, simplifying logics by replacing the control code having the hamming distance of one by a bit meaning 'don't care' on the group basis, generating AND gates for the control codes and the input signal names in each of the groups having the same input signal name and combining the outputs of the AND gates, generating AND gates for the control codes in each group having the same output destination signal name and combining the outputs of the AND gates for each of the output destination signal names, and combining the outputs of the groups each having the same input signal name and the groups each having the same output destination signal name.

Decoding type select logic generating method

An automatic design system of a logic circuit system includes a storage for storing information about structures and functions of known basic circuits available for a circuit system to be designed, an input device for receiving design specification information about the structures and functions of the circuit to be designed, and a synthesize section for combining the known basic circuits stored in the storage so as to synthesize the desired logic circuit satisfying the design specification information.

Automatic design system of logic circuit

A production system for an expert system comprising: a production rule memory unit storing circuit conversion rules, each having a condition part describing circuit connection and an execution part describing a conversion of the condition part to an equivalent logic circuit dependent upon a predetermined semiconductor technology and further having a provisionally predetermined priority; a task data memory unit storing circuit connection data, each being subjected to an application of the circuit conversion rules; a production rule interpretation and execution unit for selecting a circuit conversion rule in accordance with the provisionally predetermined priority, collating the condition part of the selected circuit conversion rule with the circuit connection data to determine whether the condition part matches with a part of the circuit connection data and, when the both match each other, converting the part of the circuit connection data by the corresponding execution part of the circuit conversion rule to an equivalent logic circuit; further each production rule being provided with a rule flag indicating the collation failure to the circuit connection data, a rule flag memory unit for setting the rule, flag of the circuit conversion rule of which condition part did not match with any of the circuit connection data during the collation cycle, so as to inhibit collation thereafter until collation of all other circuit conversion rules is once completed, thereby increasing the operation speed of the production system for an expert system.

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Hitachi, Japan

Keisuke Bekki