Abstract: A processor bus linked with at least a processor, a memory bus linked with a main memory, and a system bus linked with at least an input/output device are connected to a three-way connection control system. The control system includes a bus-memory connection controller connected to address buses and control buses respectively of the processor, memory, and system buses to transfer address and control signals therebetween. The control system further includes a data path switch connected to data buses respectively of the processor, memory, and system buses to transfer data via the data buses therebetween depending on the data path control signal.

Abstract: An interruption control device for controlling interruption requests in a multiprocessor system having a plurality of processor elements and a plurality of peripheral devices. The interruption control device is connected between the processor elements and the peripheral devices. The interruption control device includes a plurality of interruption request registers for indicating the occurrence of an interruption request from either a processor element or a peripheral device to a processor element and a plurality of interruption enable registers for authorizing an interruption request of a processor element. The interruption request registers are read by the processor element being interrupted to identify the source of the interruption request.

Abstract: A bus system for an information processing system in which data transfer among plurality of modules is controlled on a common bus. In response to a bus use request from a module, a command is issued for aborting data transfer being performed by another module having a lower priority. The module which is transferring the data responds to the abort command by issuing a signal indicating that a word being transferred is the final word. The data is transferred between a master and a slave through an address bus having a same width as the data in synchronism with a clock supplied from a bus controller.

Abstract: A plurality of process requests generated from processing units, for example, direct memory access (DMA) channels are controlled by a preference circuit in accordance with a priority level assigned to each of the processing unit. An information of the highest priority obtained processing unit and its priority level is stored in latches. Another process requests having the same priority level as the stored processing unit are inhibited from being supplied to the preference circuit, so that the first generated process request is accepted and executed prior to acceptance of the another process requests having the same priority level.

Abstract: A bus master and a plurality of bus slaves are connected through a data bus and a control bus, and data transfer of hand shake system is performed. In the control bus, at least data strobe signal from the bus master to the bus slave and data confirmation signal from the bus slave to the bus master are transmitted. The data strobe signal from the bus master is one inputted to a bus strobe control circuit. The data confirmation signal from the bus slave is also inputted to the bus strobe control circuit, and the control circuit supervises level of the data confirmation signal being asserted and confirms negation, and then asserts the data strobe signal to the bus slave. Thereafter, a next data transfer is started.