| 摘要 |
PROBLEM TO BE SOLVED: To remarkably reduce the power consumption of a system formed of a data processing device while maintaining or increasing the processing capacity of the system in the data processing device in which a CPU performs a specified processing while gaining an access to an external memory such as an SDRAM. SOLUTION: This data processing device comprises the CPU 21 for performing the specified processing while gaining an access to the external SDRAM 31 and an SDRAM controller 24 for controlling the access to the SDRM 31 based on a request from the CPU 21. The operating clockϕ1 of the CPU 21 is set to a relatively low speed, and the operating clockϕ2 of the SDRAM controller 24 is set to a relatively high speed.
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