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lpc43xx EMC时钟能等于100MHz吗?

Question asked by 彦成 曹 on May 5, 2019
Latest reply on May 24, 2019 by 彦成 曹

      板子设计时没有注意到勘误手册上说明的EMC问题,导致直接使用了clk0驱动两片SDRAM,在调试的时候直接使用系统时钟204mhz,初始化sdram是失败的,后来找到勘误手册上的一段话“ When operated in the divide by 2 mode (EMC_CLK_SEL, bit 16 CREG6, Address0x4004.312C), the duty cycle of the clock is not the typical 50 % which shortens the setuptime. This could impact designs with an EMC running faster than 100 MHz in divide by 2mode (which corresponds to a maximum core frequency of 200 MHz)

   我理解的大概意思是,EMC的时钟不能超过100MHZ,也就是系统和时钟不能超过200MHZ,我尝试把系统时钟降到200MHZ,sdram初始化成功了。但是我想知道这个不超过100MHZ能等于100MHZ吗,长期运行会不会有问题。虽然官方也给出了超过100MHZ的解决办法。但目前不想改硬件。

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