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LPDDR4 speed for EVM

one and zero
Mastermind 18136 points
Part Number: TDA4VM

Hi Champs,

our TRM for the EVM states:

However the current SDK which is using 4266 MT/s frequency configuration(Linux SDK 8.2 : board-support/u-boot-2021.01+gitAUTOINC+44a87e3ab8-g44a87e3ab8/arch/arm/dts/k3-j721e-ddr-evm-lp4-4266.dtsi).

This is clearly a mismatch. We either need to fix our EVM documentation or the SDK. Some EVMs seem to work with 4266 others only with 3733 Mb/s as documented in the EVM TRM. Please shed some light on that, thanks.

Kind regards,

one and zero

  • 0
    TI__Mastermind 38150 points

    Juergen,

    J721E supports LPDDR4-4266. The EVM documentation would need to get updated.

    Regarding some boards working and some not working, do you have revisions of the SOM being used? I assume you are using SDK8.2? 

    Note that post char, we found an issue on some customer boards and the SK board that requires an update to write DQ training parameters. You might try re-building with the attached configuration to see if that has any impact on the failures.

    https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/791/k3_2D00_j721e_2D00_ddr_2D00_evm_2D00_lp4_2D00_4266.dtsi

    Regards,
    Kevin

  • 0 in reply to Kevin S
    TI__Guru 51635 points

    I will get EVM User Guide updated to reflect 4266. I'm not aware of any SOM versions limited to 3733 speeds. We did make some power changes for LPDDR4 in later updates, but my understanding was the older SOM version(s) operated at 4266.

  • 0 in reply to Kevin S
    Prodigy 170 points

    Hi Kevin,

    Working and non working Board both has same SOM revisions.

    With provided configuration(k3-j721e-ddr-evm-lp4-4266.dtsi) board is working fine.

    Is this change missed in current SDK 8.2?

    Is it planned to release with upcoming TI SDK released?

    Thank you,

    Nikhil