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C6748 SATA drive access

Scott Colson
Prodigy 190 points

Hi,

 

I would like to set up a SATA drive on a L138/C6748 evaluation board as a mass storage device on the host through the USB port but I also need to access the drive directly from the C6748.  i.e. Create a file using the C6748 and then open that same file on the host.

To accomplish the task, I started with the example project usb_dev_msc_sample.pjt which is part of BIOSUSB 01.10.01 located in 

C:\Program Files\Texas Instruments\biosusb_01_10_01\packages\ti\biosusb\examples\usbdevmsc\build\C6748\ccs3.

This project works fine as a mass storage device but I am unable to access the drive from the C6748.  It appears that the call to dsp_bios_entry(NULL); which sets up the USB Mass Storage Device Stack is preventing access to the drive locally.  I can't find any documentation on the function so I'm not sure how it is implemented.

What should I do?

Thanks,

Scott

  • 0
    TI__Expert 7435 points

    Scott,

    When a given partition on a device/device (that has only 1 partition) is exposed as a MSC device to a PC host either C6748/PC Host(Windows, Linux etc.) can have access over it.  Simultaneous access over the filesystem will corrupt the file system on the partition and hence such an access is blocked by design.

    This is the reason you would not be able to access that partition from C6748 when that partition is exposed as a MSC device over USB to PC.

    The way you would implement the same would be to (not connect the USB cable to PC) open the partition in C6748 do all the operations on it say creating file, editing, deleting etc. Once you have completed using that partition in C6748 then connect the USB cable to PC.  Now PC can see the required information on the exposed partition and can manage it.

    In summary only one filesystem can have control over a given partition at a given point in time - either C6748 FS or PC host FS.

    regards

    swami