Program the DLL by writing to these registers in the SD_eMMC register module.
- Disable SD clock by writing 0 to the CLK_CTRL [SDClkEn, 2] bit.
- Select the TX tap by writing to the [sel] bit field.
- Program new input tap value using the register.
- Disable clock output. Write 1 to the [change_window] bit.
- Write new input tap value. Write 1 to [dly_en] and tap value to [sel].
- Enable clock output. Write 0 to the [change_window] bit.
- Wait for the SD clock to stabilize. Read CLK_CTRL [IntClkStable] bit until it is = 1.
- Enable the SD clock. Write 1 to [SDClkEn].