| 摘要 |
PROBLEM TO BE SOLVED: To retain correct data even if there is an instruction for a writing access of data during a self-refresh operation. SOLUTION: A semiconductor device comprises a DRAM 30, a cache memory 14 for retaining data of the DRAM 30, a CPU 12 connected with a bus 11, and a DRAM control circuit 16 connected between the bus 11 and DRAM 30 and performs access control to the DRAM 30 according to the access instruction transmitted from the bus 11. The DRAM control circuit 16 is provided with a bus control circuit 16a for receiving the access instruction transmitted from the bus 11 and transmitting a response to the bus 11 after performing designated control processing, a register 16b for performing motion setting of the DRAM control circuit 16, a signal generation circuit 16c for generating control signals to the DRAM 30, and a FIFO buffer 20 for retaining contents of the access instruction when detecting the access instruction transmitted from the bus 11 during a self-refresh mode of the DRAM 30. COPYRIGHT: (C)2007,JPO&INPIT
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