| 摘要 |
PURPOSE:To improve both operability and certainty of key input by providing a detecting circuit of N-key roll-over system and another detecting circuit of double key lock-out system and supplying selectively the signal sent from an output line to one of both circuits to set either one of both systems. CONSTITUTION:A key scan data generating circuit 5 supplies signals successively to each input line of a key matrix circuit 4. In addition to this circuit 5, detecting circuits 8 and 9 of N-key roll-over system and double key lock-out system respectively are provided. The output signal from each output line of the circuit 4 is selected by a data selector circuit 7 for each output line and supplied selectively to either one of circuits 8 and 9. The key codes delivered from the circuits 8 and 9 are stored in buffer circuits 19 and 12, and the fetching of data is inhibited by an AND gate 15 to the circuit 19 or 12 corresponding to the circuit 8 or 9 with the signal input to either one of circuits 8 and 9. Then the fetching of data is inhibited to the circuits 19 and 12 when the circuits 8 and 9 deliver error detecting signals. |
