| 摘要 |
A scan separator in a large scale integration device is made intensive to suppress the circuit scale of the entire device from increasing. A scan separator is provided for every two signal lines interconnecting two combinatorial circuit blocks. Each scan separator includes one selector, a flip flop for constituting a scan path, and another selector for selecting one of the two signal lines. As an input selector signal for the other selector, data for switching controlling are used, which are transferred from a test input terminal over the scan path and latched by the flip flop. The data for switching controlling are initially transferred over the scan path to each flip flop. The other selector is switched in accordance with the switching controlling data stored in the flip flop to select one of the two signal lines. The switching controlling data may be interchanged to select the other signal line.
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