International Business Machines Corporation

Wei-Wha Wu

Joseph C Logue

John C Hsieh

A logic array includes a matrix of logical elements located at the intersections of a plurality of input and output lines. Due to the nature of the array structure, more than one output line may be activated by a given digital bit pattern placed on the input lines. In testing the array, the lack of a one-to-one correspondence makes it difficult to determine if the personalization associated with a given output line is proper. The output line interference problem is solved by providing a deletion control line which may be selectively connected to any combination of output lines to thereby disable the connected output lines. Thus, a given output line may be personalized, tested and the disabled, to preclude interference between the tested output line and the remainder of the lines to be tested. Moreover, since the logic array is tested one line at a time, provision can be made for substituting spare output lines for defective output lines, thereby rendering a defective array usable.

Testing of logic arrays

A modular system comprising a microprocessor having a system bus (control address and data) and one or more programmed logic arrays connected to said system bus. Three system configurations are shown by way of example, Macroprocessor, Peripheral Input/Output and Direct Memory Access applications. The microprocessor executes a standard set of instructions and addresses each programmed logic array. Each array executes a specific instruction, beyond the standard set of instructions, upon receipt of its address.

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Poughkeepsie, NY, United States of America

Wei-Wha Wu