| 摘要 |
PROBLEM TO BE SOLVED: To reduce the scale of a circuit for self test at the point of circuit constitution connecting and isolating test paths between circuit modules mounted on a semiconductor integrated circuit. SOLUTION: Test paths 7, 8 are formed between a plurality of circuit modules 2, 3, 4 in which self test circuits are included. Pattern compression circuits 32, 42 are arranged in the upper stream of the test paths, and pattern generating circuits 31, 21 are arranged in the downstream of the test paths. At least, either one of them has a gate means which hinders selectively signal transmission through the test paths. Since connection and isolation of the test paths are possible, the self test of an independent circuit module can be ensured, and the self test is possible while considering the mutual relation of circuit modules. It is unnecessary to add a scan path register only for the connection and isolation, so that the scale of a circuit for self test can be reduced.
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