| 摘要 |
PURPOSE: To inhibit the output of the serial data before the power voltage is set at a level where an output circuit can have a stable operation by generating an output grant signal when a fixed time passed after the power voltage is set at a prescribed level higher than the lower limit level of the IC operating voltage and granting the output of the serial data by the output grant signal. CONSTITUTION: The power voltage is inputted to a power monitor circuit 1 and always compared with the prescribed voltage so that the grant necessary condition is satisfied for output of the serial data when the power voltage exceeds the prescribed level. At the same time, a timer part starts its operation and the output full necessary condition is satisfied. Then a flip-flop is set and an output grant signal is set at logic 1 for the first time. The serial data and the output grant signal are inputted to an AND circuit 2 and the output of the serial data is granted for the circuit 2. Then the grant signal is inputted to an output circuit 3, and the serial data outputted from the circuit 2 secure the interface with a serial data bus connected via the circuit 3. Thus the serial data undergo the prescribed conversion and then are outputted. |
