| 摘要 |
PROBLEM TO BE SOLVED: To improve the efficiency of signal transfer on a bus by preparing bus transfer end signals on a bus system exclusively for an address signal and a data signal respectively. SOLUTION: When a 1st bus master 210 sends a bus request signal BR-P1 out, an arbitrating circuit 250 sends a bus grant signal BG-P1 to the bus master 210 to supply an address signal to an address bus. The arbitrating circuit 250 selects, e.g. a DRAM 230 with the address signal and sends a select signal ME-DRAM. When preparations for address signal fetch are made, the DRAM 230 asserts an address acknowledgement signal AA and sends a specific number of address signals from the bus master 210 to the DRAM 230 in order to transfer data. The arbitrating circuit 250 monitors the signal AA and resets the signals ME-DRAM and BG-P1 after the address signals are transferred, thereby sending a bus grant signal BG-P2 to a 2nd bus master 220 having sent a 2nd bus request BR-P2 out.
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