C6678 SPI BOOT ddr boot table problem

Hi, TI guys!

I have successfully booted  my evm board through spi boot with the ddr boot table i found from the forum. But the are 3 fields, PLL Prediv, PLL Mul, PLL Post div still bothering me. The spi boot doc doesn't have a clear describtion about the meaning of these 3. In the para table I found from forum, the 3 field are set as follow:

00 00 00 00 // pll prediv

00  00  00  1c// pll mul

00 00 00 02 // pll postdiv

And the DDR input clk in C6678 evm is 66.667MHZ, so how do these 3 parameters(mul = 28, div =2 ??) work to derive the needed 666.67Mhz ddr rate in EVM? And since I am gonna use spi boot on my own board with ddr input clk 200Mhz, how shall I change this 3 parameters to create a 666.67Mhz ddr rate?

Thanks!

David Yang