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OMAP-L138 SD card density support?

PaulSchoenke
Genius 3290 points
Other Parts Discussed in Thread: OMAP-L138

Hello:

I am working on a project where I've targeted the OMAP-L138 processor.  With a fully populated 16 channel data acquisition system the front ends will be producing about 256Mb/s and maybe a bit more for the decimated display information.  I had planned to try and stream this on to a microSD card using the SDIO port.  However, the SDIO port has a maximum clock rate of 52MHz. and therefore has a maximum transfer rate of around 200Mb/s.  I am hoping that I might be able to get around this by attaching some NAND Flash to the EMIFA bus, which at 100MHz. and 16 bits would be able to handle 400Mb/s assuming 4 clocks per transfer.  The data sheet shows a connection to a 1G x 16-bit chip giving 2GB of storage.  What I need  to know is how large a NAND Flash may be supported per chip select?  The microSD cards are available in sizes up to 64GB per card.  Also, are there enough bits of ECC support for that large of NAND flash devices?

Any feedback or input is welcomed and appreciated!

Thanks for your help.

Best regards,

Paul

  • 0
    TI__Guru 64470 points

    I'm a bit confused because it appears you are mixing interfaces and non-volatile memory types.  Which memory type are you asking about 64GB capacity?

    NAND Flash - parallel
    SD Card - SDIO interface

  • 0 in reply to BrandonAzbell
    Genius 3290 points

    We had originally planned on using the OMAP’s MMC/SDIO port to connect to a microSD memory card.  These cards have capacities up to 64GBytes.  However, the port on the OMAP has a maximum clock rate of 52MHz which supports a maximum of 208Mbits/s.  Given that our DAS platform can have up to 16 channels of 16 bit data all running at 1MS/s, the combined rate is 256Mbits/s.  This means that the port on the OMAP will not do the job.  We had planned on using the OMAP’s second SDIO port to control the WI-FI board in the system.  If we use the OMAP’s EMIFA port instead,  it should be able to transfer that amount of data at the rate we need except that taking a quick look at NAND Flash specs the Flash may work for us if we are able to connect somewhere around 64GBytes.  However using the NAND Flash chips would mean that after an acquisition the data would need to be transferred to a removable media and take more time.  A third alternative is to buy a SDIO IP for the FPGA in the system.  I have come across one that claims to be able to run at up to 200Mz. or some 800Mb/s.  I suppose that if I really get desperate I could stick a removable SATA drive into the mix.  I hope that this has helped to unconfused you about the project mass storage ideas.  Thanks again for all of your help.

  • 0 in reply to PaulSchoenke
    TI__Guru 64470 points

    With that amount of data required and the bandwidth needed, it seems you would need to use the SATA interface or the external IP that you mentioned.