| 摘要 |
PURPOSE:To reduce the load of a CPU, by permitting the generation of polling of the CPU only when a keyboard requests data transmission to the CPU. CONSTITUTION:When a key is not depressed, a keyboard controller 221 does not store data to be transmitted to the CPU 21. When the controller 221 does not store the data to be transmitted, a request line driving means 225 turns a request line 24 off. A request line detecting means 212 detects that the line 24 is off and transmits the detected result to a polling means 211. The polling means 211 detects that a keyboard device 22 does not request data transmission by the signal from the detecting means 212 and inhibits the generation of polling to a serial data transmission line 23. |
