BUS CONTROL CIRCUIT FOR SYSTEM APPLYING MICROCOMPUTER

摘要

PURPOSE:To ensure a dynamic change of a system constitution, by connecting a matrix switch which is controlled by a storage program system to a bus of a system applying a microcomputer. CONSTITUTION:A main CPU part 4 can access only to the normal data and the part connected to an address bus 3. The buses 2 and 3 are connected when the part 4 connects matrix switches MXSW2 and 3 under the control of a switch control CPU part 6 which has an access of the control data given from a circuit 7 containing an ROM and an RAM. Thus accessing possible for the signal given from the part 4 to a circuit connected to buses 2 and 3. At the same time, the part 4 controls the part 6 and connects buses 1 and 2 with connection between MXSW1 and 2. Then the bus 3 is separated from other buses by means of a MXSW3. As a result, it is possible to use freely a bus for the part connected to buses 1 and 2 while the CPU part is processing data. It is also possible to transfer data to a masking circuit 8 from the part 4 to apply masking.