
1.Read SDCLK default setting
  SCTS_TuneClk 0

2.Set SDIO clock freq to 25 MHZ
  SCTS_TuneClk 1 

3.Set SDIO clock freq to 50 MHZ
  SCTS_TuneClk 2 

4.Set SDIO clock freq to 12.5 MHZ
  SCTS_TuneClk 3 


