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AM335x BeagleBone MMCSD and USB host work slowly

Iulian Gheorghiu
Intellectual 505 points

Hy!

I use StarterWare AM335X_StarterWare_02_00_00_06, and I have a problem:

The SDMMC read speed is around 600KB/s, and USB host read speed is around 1450KB/s for a USB flash memory and aproximately 2.4MB for a .

I think that these speeds is very low comparative with cpu and interfaces speed.

I mention that I enable the Icache and Dcache, for both interfaces I use DMA transfer for both , USB.is set to HI speed, and the clock for SDMMC module is 48Mhz.

If someone know what is the reason of these low speeds please help.

  • 0
    TI__Intellectual 1640 points

    Hi Iulian,

    How are you measuring performance , with the file system or is it the raw reads and writes.

    The best raw  read speed ( with out the  File system) I have obtained on the AM335x evaluation board was around 8 MB/s with DMA.

     Could you please give me the following information

    1. Are you using any custom board or is it any of the TI recommended evaluation boards?

    2. what is the Raw read and write speed that you are getting ? - with out the FAT file system -

    (use the  USBHMSCBlockWrite () , USBHMSCBlockRead() function to obtain the same.)

    Please use the latest StarterWare release package AM335X_StarterWare_02_00_00_07 package for the above experiment.


  • 0 in reply to Vineeth Balan
    Intellectual 505 points

    Good morning Vineeth Balan

    I already use USBHMSCBlockWrite () , USBHMSCBlockRead(). I use USB driver from AM335X_StarterWare_02_00_00_06 adapted to work with Dcache enabled.

    I use my own FAT library (created by me), and this library has been made to work with pages(512Bytes) not with clusters for devices with less RAM , for this reasons read and write at one page level(512Bytes).

    I made modifications on my library to work with clusters, and the result is:

    4.8MB/s 4KB cluster FS read from USB.

    3.2MB/s RAW Read from MMCSD class4 4KB cluster.

    Thank you very much, and I am very sorry for this my mistake.