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AM5718: DDR memory multiple speed grades

Nicholas DiNino
Prodigy 240 points
Part Number: AM5718

From customer:

We are going to use 2 different speed grade DDR3 devices for both the dual core AM572x and single core AM571x processors.  The 2 speed grades are 1866 and 1600 with 1866 being the primary speed grade DDR.  If we want to have one configuration file for each processor should we use the DDR datasheet timing for 1866 or 1600 to make the processor compatible with either speed grade memory?

Do you have general advice or feedback regarding this scenario?

Please let me know if you need additional information.

  • 0
    TI__Mastermind 26215 points
    Nick, unless I am missing something here, AM572x supports DDR3-1066 and AM571x supports DDR3 - 1333....
  • 0 in reply to Rogerio Almeida
    Prodigy 20 points
    Nick sent this question for me. To elaborate we are currently using the same DDR that is being used on AM572x Evaluation Module. The part is micron MT41K256M16TW‐107:P which is an 1866 speed grade part. We also have a second source DDR with a speed grade of 1600. So when using the AM57x EMIF tool to create the processor registers which timing should we use 1866 or 1600 so the processor will run both DDR speed grade parts?

    Thank you
    Brian Carpenter
  • 0 in reply to Brian Carpenter83
    TI__Genius 12740 points

    Brian,

    I am assuming you will be configuring the controller to run at the same speed (e.g. 1066) regardless which DDR part is used. As explained in this app note (http://www.ti.com/lit/an/sprac36/sprac36.pdf) the actual fine tuning of the DDR interface is performed by the controller (HW leveling) with the spreadsheet providing seed values to ensure convergence of the leveling algorithm. 

    Two DDR parts you plan on using have different specs and the spreadsheet will most likely produce different seed values for each one. It is possible that the HW leveling on one DDR part will succeed even with seed values calculated using another part's spec, however it would be much safer to go through DDR configuration exercise separately for each part you plan on using and keep both sets of configuration parameters in your boot code. 

    Regards,

    Michael