| 摘要 |
The method is used for parallel built-in testing of RAM, and provides simplified management of additional hardware devices when a built-in test function is provided. According to this method, the test sequence for a k-neighbourhood in a 2D memory matrix is given by 2<q> alternating sequences, where 2.(2<q> - q) is less than or equal to k; these sequences are obtained from arbitrary sequences of cells in each neighbourhood via "cut" and "join" operations. Within each neighbourhood, the first and last cells switch most frequently from one cell to the next. In this case, the cells can be divided into k q-groups; for each group, the two switching sequences will include at least one pair of cells within a single group that switch in reverse order, while the remaining cells in the neighbourhood switch differently-either an inner cell or an outer cell, adjacent to at least one of the pair. A 2<k-q-1> background is written within each group, so that the codes within any arbitrary k-q-cell of a neighbourhood that belongs to different groups, with any two backgrounds having a Hamming-code distance d = {1, ., k-q-1}, and each background covers two fifths of each switching sequence.After switching one or more cells, the state of the cell(s) just switched will be verified before the neighbouring cells or the second-nearest-neighbour cells are switched.
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