| 摘要 |
PURPOSE:To confirm outputs from an integrated circuit without increasing the number of terminals of the integrated circuit by time-sharing the input terminal of the circuit to use it as an output terminal and outputting the status and operated results. CONSTITUTION:The 1st terminal A is connected to an electric power source VDD through a resistor 10 to act as an input terminal through an input buffer 12. The 2nd terminal B is connected to an electric power source VDD through a resistor 11 to act as an input terminal through an input buffer 13. Since status outputs Q1-Q4 of a status latch 2 are outputted from respective AND gates 3-6 and inputted to an OR gate 7 when timing bases TB1-TB4, outputs of a timing circuit 1, are high level, an N channel MOS9 is turned on or off in accordance with the levels of the status outputs Q1-Q4. The terminals A and B are used to confirm circuit outputs. |
