i think that is because the data will transfer in two direction , for the MCLK is comes from controller ,if you used the MCLK to sample the data output from DDR you will have some trouble in sync between data and clk,it easier to control the timing when using the DQS come out from memory together with data signals.
i think that is because the data will transfer in two direction , for the MCLK is comes from controller ,if you used the MCLK to sample the data output from DDR you will have some trouble in sync between data and clk,it easier to control the timing when using the DQS come out from memory together with data signals.
ok, Thats mean MCLK can not be used for read data, But MCLK can be used for write data(As ctrl drives MCLK and write data). then why strobe is used to write data into memory