| 摘要 |
PROBLEM TO BE SOLVED: To easily form a test pattern for DC test by connecting two input terminals of a data selector to a scanning input terminal and the data output terminal of scanning FF at the final step and connecting the output terminal of the selector to the scanning output terminal. SOLUTION: Data selectors 24 and 44 electrically connects between scanning output terminals 22 and 42 corresponding to the logic values of signals input in scanning select terminals 30, 32 and 50. Therefore, when scanning input terminals 20 and 40 and scanning output terminals 22 and 42 are directly connected at the selector 24 and 44, the test pattern input in the input terminals 20 and 40 appear as it is in the output terminals 22 and 42 and so data are not needed to shift between each scanning FF 14, 16, 18, 34, 36 and 38. Thus, the test pattern for DC test used in this scanning circuit 10 is completed in 2 steps input by logic value 1 and 0 in each of scanning input terminals 20 and 40 and so forming is easy and the length of the test pattern can be shortened. |
