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Altera_Forum's avatar
Altera_Forum
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16 years ago

Who have the code of Scatter-Gather DMA?

I meet a lot of problems of Scatter-Gather DMA,i do not have the example of Scatter-Gather DMA.it is very hard to make it.some one who have the code of Scatter-Gather DMA please upload it.

thanks in advance

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Here you go: http://www.altera.com/support/examples/nios2/exm-scatter-gather-dma.html

    There will be a new "Modular SGDMA" that will be posted up on the Nios II design examples page shortly. It doesn't use descriptor fetching and as a result is much easier to use in my opinion. If you want to take a look at it send me a message with your email address and I'll forward it to you. This is the Modular SGDMA feature list that isn't present in the SGDMA today:

    • Up to 4GB transfer lengths

    • ST-->MM early termination (packet length limiting)

    • Interrupts per descriptor

    • MM-->ST error signal

    • Burst boundary re-alignment

    • Park mode built into the descriptor (makes frame buffering easy)

    • Descriptor sequence numbering (tag the descriptors then readback from the SGDMA to find out which descriptor the read and write masters are working on)

    • Descriptor programmable burst

    • Descriptor stride (address increment for fixed/interleaved data)

    • Data widths up to 1024 bits

    • Independent reads and writes (i.e. descriptors are dual buffered so the write master does not block the read master from starting up again)

    • Burst lengths up to 1024 beats

    • User selectable data/descriptor FIFO depths
    -JCJB
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    thank you for your suggestion,but i want to learn the descriptor to control the SGDMA,so i wish you give me an example of the SGDAM.

    my mailbox address is:

    li_polaris_1988@yahoo.cn

    thank you very much
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    It was moved to the alterawiki. If you search for "modular SGDMA" on the wiki it should bring you to the correct page.