| 摘要 |
PURPOSE:To most suitably arrange the contention of bus use by receiving bus use request signals, whose priority levels are determined, from a priority level converting circuit and outputting a bus use permission signal to the bus connecting device which outputs the bus use request signal having the highest priority level. CONSTITUTION:A priority level converting circuit 9 determines priority levels of bus use request signals (b) from bus connecting devices on the basis of a priority level indicating signal (d) from a device deciding circuit 7 and outputs theme to a preferential device selecting circuit 8. This circuit 8 receives bus use request signals (b), whose priority levels are determined, from the priority level converting circuit 9 and outputs a bus use permission signal (c) to the bus connecting device which outputs the bus use request signal having the highest priority level. The bus connecting device which receives the bus use permission signal (c) from the preferential device selecting circuit 8 is permitted to use a bus 1 and transmits and receives signals to and from another device, which is connected to the bus 1, through the bus 1. Thus, the contention of bus use is most suitably arranged. |
