| 摘要 |
PROBLEM TO BE SOLVED: To shorten the occupation time of a multisystem bus and to prevent the oppression of the arithmetic processing time by deciding the presence or absence of an access which is given to an input/output part from an arithmetic processing part, outputting the accumulated input data to the arithmetic processing part and also accumulating the output data given from the arithmetic processing part. SOLUTION: A buffer part 21 decides whether the IOAC signal received from an arithmetic processing part 11 is valid or invalid and accordingly decides the presence or absence of an access which is given to a DIO part 15 from the part 11. A data accumulation part 21b of the part 21 accumulates the DI data at the time excluding the access given to the part 15 from the part 11 and outputs the DO data. Thus, it's possible to shorten the occupation time of a multisystem bus 12 when the part 15 is accessed and also to prevent increase of the time needed for acquisition of the bus 12 when a CPU card 11a transfers the data. |
