| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of terminals of an LSI chip, by a method wherein a usually used terminal is used temporarily as a test terminal so as to test an LSI. SOLUTION: In a test mode, a test mode signal TE is set at '1', and a selection switch circuit 6 is set to the side of '1'. After that, when test code signals S1, S2 are inputted from output terminals 12, 13, the test code signals S1, S2 are inputted to latch circuits L1, L2 through amplifier circuits 17, 19, AND circuits A1, A2 and flip-flops F1, F2. After that, when an LSI is reset, amplifier circuits 15, 16 are turned off, the latch circuits L1, L2 latch the test code signals S1, S2. After that, selection switch circuits 7, 8, 9 are changed over by the latched test code signals S1, S2, and a test signal is fetched from an output terminal Z via the selection switch circuit 6. When the test mode signal TE is set at '0', the selection switch circuit 6 is set to the side of '0', and a usual output signal is outputted from the terminal Z. |
