| 摘要 |
<p>PURPOSE:To prevent time from being shifted for exchanging time data by connecting a processor through a common bus to a real-time clock for bus possession control to receive access from each processor. CONSTITUTION:A bus possession control part 6 is provided while being connected to buses 3-1-3-n and control lines 4-1-4-n from respective processors 1-1-1-n so as to connect each processor through a common bus 5 to a real-time clock 2 according to this access. In this case, in order to perform access from the respective processors 1-1-1-n to the real-time clock 2, it is requested through the control lines 4-1-4-n to the bus possession control part 6 that it is desired to access the real-time clock 2. Thus, the bus possession control part 6 executes selection so as to execute bus control to any one of processors, and any one of buses 3-1-3-n is connected to the common bus 5, connected to the real-time clock 2 and can be immediately accessed.</p> |
