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McBSP MCM mode

Harikrishna Vuppaladhadiam
Expert 1855 points

We would like to use multiple C64x devices which share a TDM stream.

I got a question:

   Is it possible to switch TDM slots on a DSP in a single frame say 125 usecs without disturbing or restarting whole McBSP port init. Pl. advise how to switch TDM slots? I read something about MCM in TDM mode, but was not clear if I can swap TDM ports say for example

   DSP 0 was using - slot 1, 2 of 128 time slots,

   DSP 1 was using slot 3, 4 of same TDM bus 128 time slots.

If I decide to swap the slots of DSP 0, 1 what is the best procedure? Should I restart the DSP? I am ok to lose 1 frame of tdm sample (say 125 usecs). Can anyone guide me right literature.

 

Regards,

Hari

 

  • 0
    TI__Guru* 84110 points

    Hari,

    Welcome to the E2E Forums. We apologize that it has taken so long to respond to your questions. In the time that has passed, I hope that you have been able to find some helpful information by searching these forums and by searching the TI Wiki Pages. There is a large amount of information available to you in these powerful resources, as well as the device documentation at our home site, TI Home (do a part number search in the upper-right corner at ti.com to find your device's Product Folder and all the documentation for it).

    For future posts, it will be helpful to be specific about the device you are using. C64x refers to the core in the C6414 and DM642 (and other devices); there is also the C64x+ core which is in newer DSPs such as the C6455 and C6457. Detailed answers sometimes require more specific information.

    The answer to your question is, yes, you can change TDM slots for any given DSP on a TDM McBSP port during frame operation, and without disturbing or restarting the whole McBSP port. The concept of swapping is a system-level issue that you must handle in your own application code to avoid contention or missed data on the TDM bus.

    The TMS320C6000 DSP Multichannel Buffered Serial Port (McBSP) Reference Guide explains the operations for changing the TDM slots for any single DSP. Please search for information there on subframes and partitions and Changing Element Selection. Each DSP will follow this same procedure to change its TDM slots during a frame.

    Regards,
    RandyP

     

    If you need more help, please reply back. If this answers the question, please click  Verify Answer  , below.