Control of combinational circuits by two diagnostic criteria based on boolean signal correction using the hamming codes properties

A method for synthesizing self-checking digital devices with improved testability indicators is described. The method is based on the concurrent error-detection circuit synthesis by signals Boolean correction and the Hamming code (7, 4) with control of calculations according to two diagnostic criteria. The attributes used are the belonging of code words to the code (7, 4) and the self-duality of each function describing the data and checking bits of the code. The concurrent error-detection circuit basic structure for a seven-output combinational device is giving. The structure uses standard blocks, apart from the Boolean correction function calculation block. An algorithm has been developed for the Boolean correction function calculation block synthesis that meets the conditions for ensuring the self-duality of the generated signals and the belonging of code words (7, 4) to code. The application features of the basic structure are studied. It is shown that as n increases, the technical implementation complexity of individual concurrent error-detection circuit standard components decreases in comparison with the traditional duplication method. However, due to the increase in the complexity of the comparator, the overall complexity indicators of their technical implementation are growing. This leads to a decrease in the growth of the “efficiency margin for structural redundancy” of the proposed method as n increases. Thus, the effectiveness of using the presented method compared to duplication can be achieved with a significant reduction in the complexity of individual Boolean correction function calculation blocks (considering the possibilities for joint optimization of their structures). A preliminary assessment allows to recommend the developed method for special cases of diagnostic objects with a small number of outputs (no more than 30). On a case-by-case basis, effectiveness versus duplication must be assessed. In comparison with duplication in terms of testability, the method turns out to be more advantageous, since it makes it possible to ensure the tests formation more easily for concurrent error-detection circuit elements than when using duplication and makes it possible to achieve their formation even in cases where this is impossible with duplication. The proposed method for synthesizing self-checking devices can be considered when designing highly reliable digital systems on a modern element base.