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DMA between off chip and on chip memory

Kerry Barnes
Prodigy 40 points

Other Parts Discussed in Thread: TMS320C6678

Most of what I can find on DMA discusses DMA from I/O device memory to CPU memory.  Is it possible to initiate DMA transfers between different memory areas used by the multicore processors?  For example is it possible to initiate a DMA transfer between off chip DRAM to the internal shared 4mbyte memory.  Is it possible to DMA directly between CPU local store areas?

  • 0
    TI__Mastermind 30825 points

    The EDMA can transfer data between all of these memories DDR3, Local L2, Shared L2, L1D, L1P.  You'll need to use the global addresses for the Local L2, L1P and L1D memories.  Local vs Global addressing is documented within the C66x CorePac UG.  The actual addresses for are a specific device are documented in the respective Data Manual.  You can also use IDMA for local transfers (between L1P, L1D and Local L2 of a core.)

    Best Regards,

    Chad

  • 0 in reply to Chad Courtney
    Prodigy 40 points

    Thanks - that was helpful.  you state: The actual addresses for are a specific device are documented in the respective Data Manual.  I looked in http://www.ti.com/product/tms320c6678 but saw no infomration about the base addresses of the different memories.  Am I looking at the right document?


  • 0 in reply to Kerry Barnes
    TI__Mastermind 30825 points

    Kerry,

    It's in the Data Manual (the document which is the first link on the page you provided the link to above - Here's the direct Link to the pdf.)  It's documented in the Memory Map (section 2.3), it specifies it as either Local L2/L1D/L1P or CorePac # L2/L1D/L1P.  Local is the address that the CorePac would view the address as (but could also use the global address) and the CorePac # L2/L1D/L1P is what everything outside of the CorePac # would need to use to address that specific CorePac's memories. 

    Best Regards,

    Chad