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daimatsu_kiki's avatar
daimatsu_kiki
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1 year ago

About mSGDMA core settings

I have a project in Quartus 18.0 that incorporates Nios2 for Cyclone IVE. In this project, packets received over Triple-Speed Ethernet are forwarded to an external SDRAM via mSGDMA. There is a sett...
Embedded Applications Layer
Nios Cpu
tehjingy_Altera's avatar
tehjingy_Altera
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1 year ago

Hi


The Maximum Transfer Length parameter is the maximum length a data could be stored in a descriptor.

A descriptor sets up the transfer parameters for a DMA channel transfer. If in general the data you are passing is smaller you could set this parameter to be smaller to increase the performance.


Regards

Jingyang, Teh


  • daimatsu_kiki's avatar
    daimatsu_kiki
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    1 year ago

    Thank you for your answer.


    Maximum Transfer Length parameter is the maximum value that can be set in the length field of the descriptor, isn't it?


    For example, when the FPGA receives a 1518-byte packet with 'Maximum Transfer Length=1KB', will the mSGDMA controller create two descriptors?
    (Descriptor 1: Length = 1024,
    Descriptor 2: Length = 494)


    Regards