| 摘要 |
PURPOSE:To increase the noise resistance and to decrease the time required from the pressing of a key to the generation of a strobe signal, by temporarily stopping the key scan and confirming again the output of the corresponding key switch in case a key-on signal is obtained during the scanning of the key switch. CONSTITUTION:The clock pulse is always supplied to an input terminal CK of a timing circuit 12 from a clock generator 11. The signal given from an output 12b is a period signal of twice as much as the clock pulse and supplied to the terminal CK of a counter 13. The ON/OFF state of each key switch is confirmed within a cycle of the signal which is produced from an output 12c of the circuit 12. The confirmed state is written into a storage device 18 with the timing to the signal which is delivered to an output 12d. A signal is produced from an output 19a of a strobe signal generating circuit 19 to stop the input signal of a counter 13 via the circuit 12 and then to stop the advance. |
