DLL Off to DLL On Procedure

To switch from DLL Off mode to DLL On mode, follow the procedure below:

  1. Make sure no access is in progress and Self-refresh mode is disabled.
  2. Enable Self-refresh mode and set MPDDRC_LPR.CHG_FREQ to 1.
  3. Wait until self-refresh is performed, then read MPDDRC_LPR.SELF_DONE.
  4. Change the frequency. The minimum value is 303 MHz.
  5. In MPDDRC_CR, update appropriate values: Reset DLL (DLL), CAS read latency (CAS), CAS write latency (CAS_WR). DIS_DLL must be set to 0 and DLL must be set to 1. Update other bit fields depending on the Frequency and DLL On parameter settings.
  6. Update all asynchronous timings (TRAS, TRP, TXSRD, etc.) in MPDDRC_TPR0, MPDDRC_TPR1 and MPDDRC_TPR2 depending on the Frequency and DLL On parameter settings.
  7. Perform an access to DRAM.
  8. DLL is now enabled.