BUS SYSTEM, BUS CONTROL SYSTEM AND BUS CONVERSION DEVICE

摘要

PROBLEM TO BE SOLVED: To minimize the lowering of responsiveness, bus availability and throughput caused by the competition of transactions, in a bus system where a plurality of modules are hierarchically connected through a bus. SOLUTION: A system bus 407 and I/O buses 411 to 413 are split buses and they support split transfer where the start cycle of reading access and a response data cycle can be split. When a processor 401 starts the reading of I/O 418 through a bus conversion device 410 and a system is not in the response data cycle of I/O 418, the system bus 407 and the I/O bus 413 are in usable states and therefore the transaction can be issued to I/O 419 from the processor 401 without being waited even if a processor 402 requests reading from I/O 419 of the same I/O bus 413.