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What the MMC compliance version does the ROM code in AM3352 support?

Nomo
Guru 16800 points
Other Parts Discussed in Thread: AM3352

Hi,

I am using AM3352.
I want to boot from MMC and MMC complies with MMC 4.5.
At first, the Public ROM code is copied to Public RAM Memory, and then the booting from MMC starts, I think.
Now I have a question whether the Public ROM code supports MMC 4.5.
If the Public ROM code doesn't check the revision, it is possible, I think.
Could you teach me whether my suggestion is true or not, and MMC 4.5 is supported?

Thanks

Nomoto

  • 0
    TI__Guru**** 393215 points
    Hi Nomoto-san,
     
    Do you mean MMC card or eMMC memory chip? If you mean card, then almost all SD/MMC cards should work for booting. For eMMC booting please check section 26.1.7.5.2 of the AM335X Technical Reference Manual.
  • 0 in reply to Biser Gatchev-XID
    Guru 16800 points

    Hi Biser,

    Thank you for your reply.

    Both of MMC and eMMC are OK.
    The point is whether the memory complies with MMC 4.5.

    I want to know whether the Public ROM code support MMC complying with MMC 4.5.

    Thanks

    Nomoto

  • 0 in reply to Nomo
    TI__Guru**** 393215 points
    Please read carefully the while section 26.1.7.5. Boot ROM flowchart is described there.
     
    In section 26.1.7.5.4 it's mentioned that "On MMC1, Bit30 of the response received from the card is set to 1 by the ROM, and this modified value is used as the argument for subsequent CMD1. This is done to indicate to the card that the ROM supports sector addressing. This mode might not be compatible with older (older than v4.4) versions of cards."
     
    And in section 26.1.7.5.2 - "The restriction is a result of many eMMC devices not being compliant with the eMMC v4.41 specification. If you have the need to boot from two different card cages, many MMC/SD cards will boot from MMC1, but for maximum compatibility only MMC0 should be used to boot from the card cage. Similarly for maximum compatibility, booting from eMMC/eSD/managed NAND should only be performed on MMC1."
  • 0 in reply to Biser Gatchev-XID
    Guru 16800 points

    Hi Biser,

     

    Thank you for your reply.

    And I try to read carefully and understand described.

     

    Thanks

     

    Nomoto