| 摘要 |
PURPOSE:To attain a data input/output system with a small number of signal lines by giving the serial conversion to the input/output port address of a parallel bit style, the output data and the read/write command given from the processor side. CONSTITUTION:In this system a processor side device 10 is connected to an input/output port side device 20 via a serial transmission circuit 30. A serial/parallel conversion circuit 11 receives an address AD of a parallel bit style and the output data DT from the processor and sends them by a bit to a serial transmission circuit 31 through an output terminal OUT. The circuit 11 converts the input data of a series bit style which is received by an input terminal IN from a series transmission circuit 32 via gates 16 and 17 into a parallel bit style and sends it to the processor in the form of the input data DT. A control circuit 13 supplies a display signal to the processor to display that the circuit 13 is executing an input/output action. While the processor is kept under a waiting state while said display signal is delivered. |
