Patent ID: 9091730
Filing Date: 2015-07-28
Classification: G01R,G06F

Abstract:
1. A method to detect or locate faults within N clock domains and faults crossing any two clock domains in an integrated circuit or circuit assembly during scan-test, where N>1, each clock domain having one or more capture clocks and one or more scan cells, each capture clock comprising a selected number of shift clock pulses and a selected number of capture clock pulses, each shift clock pulse comprising a clock pulse applied in scan mode, each capture clock pulse comprising a clock pulse applied in normal mode; said method comprising the steps of: (a) generating and loading N predetermined stimuli to all said scan cells within said N clock domains in said integrated circuit or circuit assembly, by applying said shift clock pulses to all said scan cells in said scan mode for loading or shifting-in said N predetermined stimuli to all said scan cells, during a shift operation; (b) applying an ordered sequence of capture clock pulses to all said scan cells within said N clock domains in said normal mode during a capture operation, the ordered sequence of capture clock pulses comprising at least three said capture clock pulses from two or more selected capture clocks, for controlling two or more clock domains, in a sequential order, wherein one said selected capture clock must contain at least two said capture clock pulses, and when detecting or locating selected delay faults within a clock domain, said selected capture clock controlling the clock domain contains at least two consecutive said capture clock pulses to launch the transition and capture the output response; and (c) comparing N output responses directly with their expected output responses for all said scan cells within said N clock domains and indicating errors immediately, by applying said shift clock pulses to all said scan cells in said scan mode for comparing or shifting-out said N output responses for comparison with said expected output responses, during a compare operation.