Information processing system and logic LSI, detecting a fault in the system or the LSI, by using internal data processed in each of them

Information processing system, including a plurality of information processing units, wherein a fault occurring in said plurality of information processing units is detected by carrying out a comparison among data being processed and output by each of said plurality of information processing units, said information processing system comprising:

• a bidirectional data transmission path for bidirectionally transmitting data between said information processing units;
• wherein each of said plurality of information processing units includes a processor circuit in which a plurality of internal circuits are integrated, an internal processing result outputting means for outputting each result data, processed by respective ones of said plurality of internal circuits, an internal data selection circuit for selecting and outputting a selected result data, output from said internal processing result outputting means, at a predetermined timing, an internal data outputting means for outputting one part of data output from said internal data selection circuit to another one of said information processing units via said bidirectional data transmission path, and a comparator for executing a comparison between the remaining part of data output from said internal data selection circuit and a corresponding part of data output from the internal data outputting means of said another one of said information processing units, and for outputting a result of the comparison.