| 摘要 |
PURPOSE:To enable to monitor the function of an inside gate of the LSI according to the plural ways and moreover rapidly only by adding one pin by a method wherein the checking function of the inside gate and the function at normal use are made to be provided to the pin. CONSTITUTION:A signal s of the inside gate intending to be outputted is inputted into a tri-state output buffer circuit 1, and when a change-over signal H is outputted from an outside terminal 6 for change-over, a check signal is generated as output at an outside terminal 5 for common use of the check signal/a normal signal, and can be confirmed. Moreover when a change-over signal L is outputted from the outside terminal 6 for change-over, the tri-state buffer circuit 1 is made to be in the high impedance condition, and the normal signal inputted from the outside terminal 5 for common use can be obtained from the output terminal of an AND gate circuit 3 through an input buffer circuit 2. |
