| 摘要 |
PURPOSE:To improve the use efficiency of a common bus by performing close control over the common bus according to operation specification and the current operation state of a communication destination control module. CONSTITUTION:A central processor or input/output controller (called a control module hereafter) when starting operating activates a common-bus use request lines REQ1, REQ2, or REQ3 firstly, and sends a request to obtain the right to use the common bus CB to a common bus controller CBC. The CBC gives the right to use the CB to one control module according to priority determined among control modules, and activates a CB permit line ACK1, ACK2, or ACK3 corresponding to the control module to send a report. The control module given the right to use the CB sends out the destination address and its control module address to an address line ADRS to display read or write operation through a read/write control line RW. |
