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[FAQ] AM623: Can eMMC0 support DDR50 mode

Tony Tang
Mastermind 28992 points
Part Number: AM623

Tool/software:

Can MMC0 port support eMMC DDR50?

In the datasheet, list only 3 modes for eMMC application. DDR50 in SD Card application but not for eMMC.

Although list all features in TRM, but we was told follow datasheet as usual.

  • 0 in reply to Prashant Shivhare
    TI__Mastermind 28992 points

    Hi Prashant,

    From software perspective, there is ti,otap-del-sel-ddr52 = <0x5>; option in dts.

    But it is not in datasheet, that is why customer ask if it support or not, The datasheet should be changed from: 

    7.11.5.16.1 MMC0 - eMMC/SD/SDIO Interface
    MMC0 interface is compliant with the JEDEC eMMC electrical standard v5.1 (JESD84-B51) and it supports the
    following eMMC applications:
    • Legacy SDR
    • High Speed SDR
    • HS200

    To:

    7.11.5.16.1 MMC0 - eMMC/SD/SDIO Interface
    MMC0 interface is compliant with the JEDEC eMMC electrical standard v5.1 (JESD84-B51) and it supports the
    following eMMC applications:
    • Legacy SDR
    • High Speed SDR

    • High Speed DDR
    • HS200

  • +1 in reply to Tony Tang
    TI__Guru 62855 points

    The design team was not able to close timing for High Speed DDR mode on MMC0 of AM62x devices. Software should exclude that mode of operation on MMC0 of all AM62x devices.

    Regards,
    Paul

  • 0 in reply to peaves
    TI__Guru 62855 points

    I made a correction to my previous post and changed my initial reference of DDR50 to High Speed DDR. 

    Regards,
    Paul

  • 0 in reply to Tony Tang
    TI__Guru**** 168211 points

    Hi Tony,

    This "ti,otap-del-sel-ddr52 = <0x5>" has been removed in SDK10.1 devicetree to align with the Datasheet.

    32ae7316ddc6 (tag: cicd.scarthgap.202410100400, tag: 10.01.03) arm64: dts: ti: k3-am62-main: Update otap/itap values

  • 0 in reply to Bin Liu
    TI__Mastermind 28992 points

    Hi Bin,

    It is recommended to limit eMMC at 50MHz in old SDK(for example SDK8.6) as not working stable with HS200, so that is not guaranteed by the device? 

    What is the suggestion for SDK8.6 user except upgrade to SDK10.1?

  • 0 in reply to Tony Tang
    TI__Guru**** 168211 points

    Hi Tony,

    SDK10.0/10.1 has some MMC driver improvement, customers should first test SDK10.0 with HS200 enabled to see if the stability problem still exists.

    If so, with HS200 disabled (remove "ti,otap-del-sel-hs200" from sdhci0 node in devicetree), the eMMC speed will be now limited to HS mode, instead of DDR52 mode as in SDK8.6.

  • 0 in reply to Bin Liu
    TI__Guru 62855 points

    From the Hardware perspective, the AM62x devices support three eMMC data transfer modes on MMC0. The modes supported are defined in the MMC0 timing section of the datasheet. The device supports eMMC Legacy SDR, eMMC High Speed SDR, and eMMC HS200 modes. The device does not support the eMMC High Speed DDR mode.

    Note: The SD Card UHS-I DDR50 is supported which may seem strange since eMMC High Speed DDR is very similar, but there are small timing differences that prevented the design team from being able to close timing for eMMC High Speed DDR mode.

    The software team found some configuration issues that could be problematic and fixed them in the SDK version Bin referenced above. I suggest you encourage the customer to use the latest MMC software driver for a more robust system.

    Regards,
    Paul