是异步DDR吗？异步的可以用高速时钟clk对DQS、DQ打两拍为DQS2、DQ2，以后都在高速时钟clk的时钟域处理。
然后对DQS2做上下边延检测,用检测的信号锁数据。

clk  __/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  \__/  

DQS ___/           \___________/           \___________/           \___________/          

DQ  ===X           X           X           X           X           X           X           X          

DQS1________/           \___________/           \___________/           \___________/          

DQ1 ========X           X           X           X           X           X           X          

DQS2______________/           \___________/           \___________/           \___________/          

DQ2 ==============X           X           X           X           X           X           X          
U   ______________/      \________________/      \________________/      \________________/      

D   ___________________________/      \________________/      \________________/      


【 在 katyusza 的大作中提到: 】
: ___     ___     ___     ___
: DQS     _________|   |___|   |___|   |___|   |__________
:         _________ ___ ___ ___ ___ ___ ___ ___ ___ ______
: ...................
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修改:netvideo FROM 125.69.13.*
FROM 125.69.13.*