| 摘要 |
PURPOSE:To easily confirm the function of an LSI, etc., by providing a circuit which latches data from an input terminal, a combinational logic circuit which inputs its output, and inputting a state change at their node to a tri-state circuit and connecting its output terminal to the input terminal. CONSTITUTION:When an input from the input terminal 1 changes from 0 to 1 at a point t1 of time, an input buffer 2, the latch circuit 3, and a combination circuit 40 generates outputs in order. Then an input from an input terminal 6 for control changes from 0 to 1 at a point t2 of time, the latch circuit 3 enters a holding state and the tri-state circuit 5 is conducted, so that the state change at the node A is outputted to the input terminal 1. The signal of this input terminal is decided at the point ts of sampling time to confirm the function of the combining circuit 40. Consequently, even when an LSI to be test can not be provided with an output terminal because of the restriction of the number of terminals, its function can be confirmed efficiently.
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