| 摘要 |
PURPOSE:To prevent data held in a RAM from being changed by providing this memory card with a circuit for delaying the operation of a control circuit when an operation control signal and a write control signal are in an operatable level and an output control signal is an operation disabled level. CONSTITUTION:In a period from the application of an external power supply up to the arrival of the voltage levels of respective control signals in an operation control signal line 5, an output control signal line 6 and a write control signal line 7 outputted from an I/O signal terminal string 2 at the operation disabled level, the delay circuit 18 delays the operation of the control circuit 9. Since the operation of the circuit 9 is delayed by the circuit 8 during the period when the control signals of the signal lines 5, 7 are in the operatable level and the control signal of the control line 6 is in the operation disabled level, a write control signal 17 to be outputted to the RAM 1 does not output the operatable level at the initial stage of impression of the external power supply, so that the data in the RAM 1 can be prevented from being changed. |
