| 摘要 |
<p>A plurality of modules (10, 20, 30) share a bus, a use-of-bus permission signal line (4) takes the form of a daisy chain, and the bus is flexibly used depending upon the tasks processed by the modules (10, 20, 30). Each of bus control circuits (12, 22, 32) of the modules (10, 20, 30) is provided with: overlapped-request discrimination means which, when the task of a high level is being processed, issues a request signal in an overlapped manner irrespective of request signals issued from other modules and which, when the task of a low level is being processed, does not issue the request signal if request signals are being issued from other modules; and continuation-of-use discrimination means which, when the task of a high level is being processed, permits the bus to be used continuously and which, when the task of a low level is being processed, abandons the use of the bus immediately after its use has been finished.</p> |
