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How to create LUT in DSP 28335 ccsv3.3?

Milarepa
Expert 1670 points

I want to create sin cos LUT and include it in my code. 

Pls let me know how to go about doing it, where to store etc.

Thanks a lot

  • 0
    Guru 192875 points
    HI Shyam,

    Did you refer this thread: e2e.ti.com/.../154414

    Regards.
    Gautam
  • 0 in reply to Gautam Iyer
    Expert 1670 points

    Is it ok to place my entire sine table in the code like:

    float sin_tab[200]={0, ......}

    Will it be better if I create the table in a notepad and include it along with my other source files.

    Is it important to force it to some exact locations in RAM.

    Can we do similar thing for inverse trig functions as well?

    Thanks a lot

  • 0 in reply to Milarepa
    Guru 192875 points

    shyam nair said:
    Is it ok to place my entire sine table in the code like:

    float sin_tab[200]={0, ......}

    Many coders opt for the above declaration.

    shyam nair said:
    Will it be better if I create the table in a notepad and include it along with my other source files.

    This will  be more structured

    shyam nair said:
    Is it important to force it to some exact locations in RAM.

    Not required but few coders like to know where exactly they get placed.

    shyam nair said:
    Can we do similar thing for inverse trig functions as well?

    I didn't get this question. You mean to say inverse trig table? Why not!

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Expert 1670 points
    Thank you very much.
    placing LUT in a notepad along with other source files and other option of placing it directly in code.............
    Both finally end up consuming RAM memory, right?...

    Thanks
  • 0 in reply to Milarepa
    Guru 192875 points

    shyam nair said:
    placing LUT in a notepad along with other source files and other option of placing it directly in code.............
    Both finally end up consuming RAM memory, right?...

    Yes you're right! But you can assign it to ROM or FLASH too with const.

    Check this thread:


    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Expert 1670 points
    Hi,
    Thanks a lot.

    I dont know much about RAM/ROM/Flash. Could u indicate which is the best location to place it and probably why.
  • 0 in reply to Milarepa
    Guru 192875 points

    shyam nair said:
    I dont know much about RAM/ROM/Flash. Could u indicate which is the best location to place it and probably why.

    This depends on your application requirement & memory management. Also, I hope you already know that IQmath  library based sine table is already available in ROM.

    Refer this if you were unaware:


    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Expert 1670 points

    Before putting a LUT, I would like to try fpu32 fast supplement lib....I have included the lib.
    But when i declare float32 atan (float32) ....I am getting an error ....not compatible with double atan(double) .....in math.h