| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a memory controller which controls a synchronous memory with high accuracy while reducing unnecessary radiation noise caused by a clock. <P>SOLUTION: A modulation clock S-clk from a spread-spectrum clock generator is supplied to an SDRAM as an operating clock during a period until time t1 and during a period from time t3 to time t4, and after time t9, wherein writing of data and output of control signals (ras#, cas#, cs#, we#) to the SDRAM are not performed. A reference clock clk of a prescribed frequency is supplied to the SDRAM as the operating clock during a period from the time t1 to the time t3 and a period from the time t4 to the time t9 wherein the writing of the data and the output of the control signals to the SDRAM are performed. Thereby, the SDRAM is controlled with high accuracy while reducing the unnecessary noise caused by the clock supplied to the SDRAM. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
