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AM6442: MMC0 and MMC1 supported modes?

Brad Caldwell
Genius 12595 points

Part Number: AM6442

We found a discrepancy between the AM6442 datasheet and TRM regarding supported modes of MMC0 / MMC1.

Our questions are:

  1. Does MMC1 support SDR104 100MBy/s?

    In the datasheet section 7.10.5.12.2 for MMC1, it lists UHS-I SDR104 as a supported mode. However, the TRM section 12.3.5.1.2 lists SDR104 as a non-supported mode for MMC1.



  2. What is fastest speed mode I can operate a uSD card on MMC0 bus?



  3. Does MMC0 support SDIO?
    The datasheet isn't too clear on this point. In table 6-53 , the MMC data signal descriptions imply SDIO mode, i.e. MMC0_DAT0 MMC/SD/SDIO Data, but I suspect that's just a documentation carryover artifact. The TRM section 12.3.5.1.2 does list SDIO as a non-supported mode for MMC0.




  • +1
    TI__Guru 64965 points

    The AM64x datasheet represents the modes which are planned to be supported by MMC1. However, the datasheet is still a draft and may change based on device characterization. We will not know for sure until the production datasheet is released along with the AM64x device being released to production (RTP). I will submit a bug report for the TRM, requesting it to align with the datasheet.

    AM64x does not support SD Card on MMC0. More details provided below.

    It was not possible to close timing on the MMC0/MMC1 ports for them to be compliant with both eMMC and SD Card standards, so MMC0 timing was optimized for eMMC and MMC1 timing was optimized for SD Card.  You may find MMC0 timing is compliant to timing requirements of some SDIO devices, but you would need to perform a detailed timing analysis using system specific PCB delays, switching characteristics, and timing requirements of each device to confirm. However, TI will not be able to provide final switching characteristics and timing requirements for AM64x until we release the RTP datasheet. 

    Regards,
    Paul

  • 0 in reply to peaves
    TI__Genius 12595 points

    Thank you for the detailed response, this answers my questions.