| 摘要 |
PURPOSE:To input and output data through software in which control data are arranged in the control order of input/output devices by connecting a strobe line in series to >=2 input/output devices which are connected through a data bus in parallel. CONSTITUTION:A strobe outputted firstly by a central controller CPU1 is inputted to a gate 7a through an output line 6a to obtain an input/output enable signal. At this time, the output of an input/output device 2a to a strobe signal output line 6b is inhibited by a gate 8a. When the enable signal is generated, a control register 9a is set to inhibit the gate 7a and signify a gate 8a. A next strobe signal is therefore passed through the input/output device 8a and similar operation mentioned above is performed at a next input/output device 2b. Consequently, the input/output device 2a generates the enable signal with the 1st strobe signal outputted by the CPU1, the input/output device 2b generates an enable signal with the 2nd strobe signal, and the system is reset with the 3rd strobe signal. |
