We need to use 400Mhz data rate DDR2 SDRAM. So, 200Mhz is the DDR Clock frequency. from MPC8349EAEC Rev 13 datasheet, ddr_clk = csb_clk*(1+RCWL[DDRCM]), ddr_clk is the controller inside module clock, clock which driven onto the actual interface is ddr_clk/2,...