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Using EDMA3 with BIOS 5.41 (Using Code Composer Studio Version 4.2.3 and C6748 processor)

Debarati Kundu
Intellectual 370 points
Other Parts Discussed in Thread: OMAPL138

Hi,

I am planing to develop some codes using EDMA3 (with/without BIOS 5.41), Code Composer Studio Version 4.2.3 and C6748 (OMAPL138)processor. I want to develop a sine wave generation by storing the sine values for one cycle in a table and then repeatedly transferring the entries of the table by self chained transfer using EDMA3. I have not programmed with EDMA before. Can you please tell me where I can start? I have downloaded the EDMA3 LLD (from http://software dl.ti.com/dsps/dsps_registered_sw/sdo_sb/targetcontent/psp/edma3_lld/edma3_lld_01_07/index.html), but I find that the codes have been developed for CCS3.3. Can you please tell me if there is any new version of the LLD available employing CCS Version 4 and OMAPL138?

Thanks,

Debarati.

  • 0
    Expert 1070 points

    Hi Debarati,

    Check out http://software-dl.ti.com/dsps/dsps_public_sw/sdo_tii/psp/edma3_lld/index.html (latest seems to be 02.11.02.04 for BIOS 6 and 01.11.02.05 for BIOS 5). In general I go to the "TI Software and Development Tools" section  find libs and datasheets.  The link you provided seems to offer an older version...I'm not sure why.

    I found that the best way to start with EDMA is with the examples in LLD. There are several docs on EDMA and I believe the LLD comes with one as well. Eric Wilbur also wrote a doc on EDMA3 programming usinf LLD which I found very useful. I don't have a link....maybe someone has one? 

    This link just talk about EDMA in general, but has some good diagrams which I thought were helpfull: http://focus.ti.com/lit/an/spraap4a/spraap4a.pdf

    I assume you're using some peripheral (McBSP/UPP ?) which is going to generate the sinewave thru an external  DAC or something. I think you'd want some EDMA channel which is programmed to perform the transfer from memory to peripheral and which gets triggered by the peripheral (like: Tx complete or Frame sync). This event would kick of the EDMA channel and when the loaded PARAM set is exhausted (end of sinewave period) you'd have the PARAM set linked to another PARAM set, such that the whole cycle starts over again (= linking). I don't think you need chaining in your case (one EDMA transfer kicking of another).

     

    Cheers,

    Dirk

  • 0 in reply to Dirk Buijsman
    Intellectual 370 points

    Hi Dirk,

    Thanks for your reply. I would check out the link which you suggested. I am using the McASP Port. I would like to use self-linking. I am storing the values of the sine wave for around 16 time periods in an array and want to send the values of the array over and over again. 

    Regards,

    Debarati.