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Original question:

AM4372: EMIF configuration tool

AM4372: Using EMIF tools with balanced-T topology

Timothy Barr
Genius 3370 points

Part Number: AM4372

Due to space constraints we are using a split tree instead of fly-by design for our DDR3 memory as shown in Micron tech note TN-41-13. I am running into some memory stability issues and think it may be due to some register settings that would apply more to a fly-by design. Do you have any suggestions on how to set up the spreadsheet? Also I notice tha when I change certain values in the spreadsheet (such as output driive impedance) that values turn red. Does that mean that the AM4372 can only set certain values?

  • 0
    TI__Guru* 92601 points

    Hi Tim, the spreadsheet should be filled out in a similar fashion, even with T-topology.  Here are some things to check:

    -Section 1B is per memory, so be sure to fill out the specs for just one device

    -the IO settings will turn red if it doesn't match the recommendations in column G.  The value can still be used however and will be appropriately programmed in the register

    -ensure DDR timings tab are filled out directly from DDR datasheet

    -ensure the Board Details tab has proper trace lengths from your board design

    -T-topology requires stringent attention to detail on the board design to match signal flight times (trace length matching, return paths, etc.).  In addition to the Micron note, there are board design guidelines in the datasheet which must also be met.  This could be where your probably lies.

    -Try testing at a lower DDR speed (303MHz) to see if the stability problems go away.  This may indicate timing issue due to layout.

    Can you give more details on how you are testing?  Are you using GEL files, u-boot, or something else?

    Regards,

    James

  • 0 in reply to JJD
    Genius 3370 points

    Thanks! Getting the proper data from the spreadsheet seems to have solved my instability issues.  The tes we are using is memtester in the Linux mainline