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Maximum Memory for SD card with OMAP-L138

sparty
Prodigy 60 points
Other Parts Discussed in Thread: OMAPL138

What is the maximum memory for the SD card that can be interfaced with OMAP L138?

It uses SD - 1.1 specification. Does the maximum supportable memory depends on this specification? If so, how much does it support?

  • 0
    TI__Guru* 83845 points

    Hi Sparty

    OMAPL138 device and the software drivers for MMC/SD will support  SD High Capacity ( v2.0 specification), so you should be able to work with 2GB (v1.1) as well as 4GB to 32GB (v2.0 specifications).

    FYI, the driver datasheet details at the following link http://wiki.davincidsp.com/index.php/DaVinci_PSP_SDK_03.20.00.08_Datasheet ( look for MMC/SD Driver Features) 

    Regards

    Mukul

  • 0 in reply to Mukul Bhatnagar
    Prodigy 60 points

    Thanks Mukul for spending time on reading my post....

    What ever the link you have posted, I could not open it. But I guess the link which you have sent, it for the DaVinci DSPs. DaVinci DSP core are part of OMAP 35x series, if I am correct. OMAP 35x series processor use MMC/SD controllers with " v2.0 specification".

    In OMAP L138, they use  MMC/SD controllers with " v1.1 specification". The below is the document I referred with.

    http://focus.ti.com/lit/ug/sprufm2a/sprufm2a.pdf

    1. So I guess it does not support " v2.0 specification". Am I correct?
    2. One more thing I want to ask is that does the Maximum memory supported by the MMC/SD controller depend on the version of the specification? If yes, where do I get more information on that?

     

  • 0 in reply to sparty
    TI__Guru* 83845 points

    Hi Sparty

    Here is the corrected link

    http://wiki.davincidsp.com/index.php/DaVinci_PSP_SDK_03.20.00.08_Datasheet

    The driver datasheet page has information specific to OMAPL1x MMC/SD driver support/features/performance etc.

    sparty said:
    But I guess the link which you have sent, it for the DaVinci DSPs. DaVinci DSP core are part of OMAP 35x series, if I am correct. OMAP 35x series processor use MMC/SD controllers with " v2.0 specification"

    I would say that the OMAPL1x devices have peripheral/module controllers that are more close/similar  to what you see on the DM64xx and DM3xx Davinci processors (if you are familiar with these devices) compared to the OMAP35x series. E.g. the EMIFA , mDDR/DDR2 controller on DM series is closer to what you also see incorporated on the OMAPL1x devices, similarly the interconnect system and bus protocols are similar on OMAPL1x and DM644x/DM3xx devices (as compared to OMAP3 being OCP based etc).

    sparty said:

    In OMAP L138, they use  MMC/SD controllers with " v1.1 specification". The below is the document I referred with.

    http://focus.ti.com/lit/ug/sprufm2a/sprufm2a.pdf

    1. So I guess it does not support " v2.0 specification". Am I correct?

    You are correct that the MMC/SD controller as per the user documentation shows support SD v1.1 specification, actually you will find this to be true even for MMC/SD documentation for DM644x and DM3xx user guides , however I think as per our testing the MMC/SD controller on these device still work with SDHC devices, and hence the offered support in the TI software collateral.

    sparty said:
    One more thing I want to ask is that does the Maximum memory supported by the MMC/SD controller depend on the version of the specification? If yes, where do I get more information on that?

    I have to admit I haven't spent much time dwelling through the specifications ( I will see if someone more knowledgeable in this area can contribute to this thread) , but looking through the specifications available for MMC at JEDEC, the high capacity (beyond 2GB) support was offered in MMC v4.2 spec ( till MMC v4.1 it seemed to limited to 2GB). Similarly if you look at the sections on "capacity" in the SD v1.1 (http://www.scribd.com/doc/13134577/SD-Memory-Card-Specifications-V10)  vs SDv2.0 specifications (http://www.sdcard.org/developers/tech/sdcard/) you will see the clear distinction on support for HC on V2.0 spec.

    Hope this helps.

    Please let us know if you have additonal questions or concerns

    Regards

    MUkul

  • 0 in reply to Mukul Bhatnagar
    TI__Expert 3425 points

    Mukul, Sparty,

    The "raw" read and write in SD v1.x doesn't have 2 GB limitations. The limitation might be while using a particular file system.

    Additionally, we have done benchmarking on other Davinci device which has an SD 1.0/1.1 using EXT2, EXT3 and VFAT file system for > 2GB cards without issue.

    Hope this helps.

    Thanks,
    Gaurav

  • 0 in reply to Gaurav Agarwal
    Prodigy 60 points

    Gaurav,

    But the "raw" read and write in SD v1.x uses 32 bit byte addressing, if I am correct.... In that case it cannot address more than 4GByte right? 

    I am very new to SD/MMC standards and I dont know much about file systems. Does the SD v1.x controller has any memory limitations? And does it support SDHC cards upto 32GB  also?

    Do you have documents to start up with these file systems concepts?

  • 0 in reply to sparty
    TI__Expert 3425 points

    High capacity(HC) cards (> 2GB) are sector addressable (512 bytes) as compared to <=2GB cards which are byte addressable. So 0x00000002 in HC cards will mean begining of 2nd sector (or 512*2 bytes, assuming 0 based).

    For file systems you can start with:

    http://en.wikipedia.org/wiki/File_system

    http://en.wikipedia.org/wiki/Comparison_of_file_systems

    Hope this helps.

    Thanks,
    Gaurav