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C6748 without external RAM nor OS

Tuyen Nguyen
Prodigy 180 points
Other Parts Discussed in Thread: OMAPL138

Hi TI experts,

This is my first time to experience OMAPL138. There are several issues that I really appreciate for your advices.

Even though I purchased OMAPL138 EVMs but I only want to experience C6748 SOM-M1 only to develop our camera device using neither external RAM nor OS.

Our design at this step is simply enough to require only VPIF and USB OTG. To be more specific, C6748 will interface with a image sensor and stream images back to PC through USB OTG.Due to cost stringency, we would like to utilize internal RAMs for program memory and programmable ROM for boot image.

Because this is my first approach to TI DSP, there are many questions that I need to search for the answers before we can officially start the project. Your expertise will help us to make a quick grasp on the technology to accelerate our development.

1. Are internal RAMs enough for StarterWare to work? How can we make it to work with internal RAM only?

2. Can we mask our final image into internal ROM and let DSP boot directly from ROM without boot loader?

3. Can we disable external RAM in the EVMs and direct it to use internal RAMs? In other words, what should we do with EVMs to start the development of our device (without ext RAM and OS).

4. Is there any existing UVC device firmware code for C6000? If there is none, a similar sample for streaming video through USB is a great help for us.

5. Is there any development manual that helps us to program with internal RAMs and without using OS?

6. Does DSP/BIOS help to reduce the development labor in our case? How much is its size when residing in the boot storage?

Thank you very much for your supports,

Best regards,

Tuyen Nguyen

  • 0
    TI__Intellectual 2620 points

    Hi Tuyen,

    I have some comments which I inserted below:

    1. Are internal RAMs enough for StarterWare to work? How can we make it to work with internal RAM only?

    The USB stack is large and will not fit in the on-chip 128KB RAM for sure. You can try to fit the Starterware example for "serial over USB" between L2 (256KB) and the 128KB on-chip RAM. Currently it is 327KB. This is not counting other code related to your application besides the necessary run-time memories needed for stacks, variables, etc. However if this is a very application specific case, you can modify the USB stack to support only what the application needs to help reduce the code size.

    2. Can we mask our final image into internal ROM and let DSP boot directly from ROM without boot loader?

    This is possible but there are associated manufacturing cost. Please contact your local TI sales or distributor for more details. Onced ROMed the code cannot be changed for that device. A more flexible alternative you may want to look into is using NOR flash. Code can out of this type of memory like SRAM albeit slower and the device can boot to NOR.

    3. Can we disable external RAM in the EVMs and direct it to use internal RAMs? In other words, what should we do with EVMs to start the development of our device (without ext RAM and OS).

    Where you program is placed is controlled by the linker command (linker.cmd) or configuration file. There's no need to disable external RAM just to force programs to run out of internal memory. For more information refer to the "Introduction to Object Modules" and "Linker Description" sections of the TMS320C6000 Assembly Language Tools User's Guide SPRU186Q.

    4. Is there any existing UVC device firmware code for C6000? If there is none, a similar sample for streaming video through USB is a great help for us.

    Our libraries do not have that capability at the moment.

    5. Is there any development manual that helps us to program with internal RAMs and without using OS?

    Refer to answer to question #3.

    6. Does DSP/BIOS help to reduce the development labor in our case? How much is its size when residing in the boot storage?

    DSP/BIOS adds some additional code and will not fit on C674x internal memories with the functions you mentioned.