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Original question:

AM6421: GPMC Burst

AM2432: GPMC burst mode work with DMA only?

Tony Tang
Mastermind 30602 points

Part Number: AM2432

Should GPMC burst mode work with DMA only? can't work with CPU accessing, am I right? 

There are many threads asked sync mode+burst mode, the answer is not supported, let customer implement by themself.

from my understanding, it is not just a register configuration to enable it. it should work with DMA, CPU access always transmit/receive one data in one assembly code only.

  • 0
    TI__Guru 54568 points

    Hello Tony,

    The above your understanding is correct .

    The Burst Mode with CPU is not effective .


    When CPU reads from GPMC:
    - Each memory read is a separate CPU instruction (LDR, STR)
    - Addresses arrive one at a time with delays between them
    - Instruction pipeline overhead prevents continuous address streams
    - GPMC burst mode cannot be utilized
    - Result: No performance benefit from burst mode

    DMA Access :

    When DMA reads from GPMC:
    - DMA generates multiple consecutive addresses rapidly
    - No instruction overhead between accesses
    - Addresses arrive as a continuous stream
    - GPMC burst mode activates naturally
    - Multiple words transferred in one burst transaction
    - Result: Significant performance improvement (3-4x faster)

    Regards,

    Anil.

  • 0 in reply to Swargam Anil
    TI__Mastermind 30602 points

    Thanks Anil,

    How do you think adding a notes in TRM or datasheet to highlight it? many users get confusing about the Burst mode. always think setting a bit can implement Burst Mode.

  • +1 in reply to Tony Tang
    TI__Guru 54568 points

    Hello Tony,

    Yes, I agree with you. We need to discuss this with the hardware team and update the TRM or datasheet

    Regards,

    Anil.