| 摘要 |
<p>An information processing system comprises: a common bus; a processor (1) connected to the common bus; and a plurality of peripheral devices (19) connected to the common bus; wherein when one of the peripheral device (16, 19) issues a request for the right to use said common bus, a bus-use-right request signal (HREQ#) is outputted to said main processor, the right to use said system bus is assigned to said peripheral device (16, 19) which has outputted said bus-use-right request signal (HREQ#) after a bus-use-right permission signal (HACK#) is outputted in response to said bus-use-right request signal (HREQ#) by said processor (1), and said peripheral device (16, 19) is qualified to function as a bus master, and when said peripheral device (16, 19) becomes inoperative to said common bus after outputting said bus-use-right request signal (HREQ#), said bus-use-right permission signal (HACK#) outputted by said processor (1) is detected, and said bus-use-right request is released after the confirmation of the assignment of the right to use said system bus according to said bus-use-right permission signal (HACK#). <IMAGE></p> |
