| 摘要 |
PURPOSE:To exactly send out an error data, by sending out an error data in case when double keying has occurred, after a retriggerable double keying monitoring timer has ended. CONSTITUTION:A key matrix 1 is scanned in order by a multiplexer 2, a position of a depressed key is encoded by an encoder 3, is sent out to a register 4, and a strobe signal from the encoder 3 is received by a double keying checking and monitoring circuit 7. As a result, the circuit 7 operates a retriggerable double keying monitoring timer. Subsequently, a signal set to the register 4 is inputted to a PROM5, and an output of the PROM5 is converted to a serial signal by a parallel-series converting circuit 6 when the timer of the circuit 7 has been released, and is outputted from a signal line 13. If the next signal STB comes the timer of the circuit 7 is being operated, an error detection signal is sent out from the signal line 13 when the timer has been released. In this way, an error data is sent out exactly without being overlapped with a key signal sent out before. |
