| 摘要 |
PURPOSE:To provide a decoder test circuit which can detect that the multiple output of a decoder signal is caused by the trouble of the decoder, and can reduce the number of circuits. CONSTITUTION:A test circuit has a sense amplifier 3 and transistors T4 to T11. The output signals (resister selection signal) R0 to R7 of a general purpose register selection decoder 1 are severally input into the gates of the transisters T4 to T11, whose sources are earthed, and drains are collectively input in the sense amplifier 3, and when the turning on of two or more of transisters T4 to T11 are detected, the test signal is output. |
