| 摘要 |
<p>PURPOSE:To facilitate an easy control of a timer in a subsystem of a data processing system when connecting loose coupling multiprocessors with a serial interface, etc. CONSTITUTION:The initialization of a real time timer is performed by a timer controller, at the system rising. The controller 6 knows that the application of an electric power supply is through with each subsystem and transmits system resetting instructions to all subsystem. Then the controller 6 transmits the timer stop instruction through a multi-address communication and sends the data and real time information together with a time setting instruction. Finally a timer start instruction is sent to give a simultaneous start to all subsystems. Each subsystem contains a clock generator such as a crystal oscillator, etc. within its own device. The timer is advanced with the clock generated from said clock generator. This clock has accuracy to attain easily 10<-5>-10<-6> orders, and therefore an error per hour can be suppressed down to about 20ms. In such a way, each subsystem can keep an accurate real time without having a complicated timer compensating circuit.</p> |
