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5505 DMA Controller - external memory access

Tommy Hongkeo
Prodigy 20 points

I have checked the documentation (SPRUF09) and it states only DMA Controller 3 has access to external memory. The examples I have looked at use channels 0-15. Are the channels mapped like this DMA Controller 0 (Channels 0-3), DMA Controller 1 (Channels 4-7), DMA Controller 2 (8-11), DMA Controller 3 (12-15)? Or do I need to set some specific attributes to use DMA Controller 3?

Also are there more examples  I can look at?

Thanks in advance

Tommy

  • 0
    TI__Mastermind 23785 points

    Try the CSL examples at:

    http://software-dl.ti.com/dsps/dsps_public_sw/dsps_swops_houston/C55X/CSL-c55x-lowpower-versions.htm

     

  • 0
    Intellectual 360 points

    Hey Tommy,

    Yes you are right. The Chip Support Library (CSL) code maps the channels in the way you have mentioned. However when you do external memory access it is only channels associated with DMA Controller #3 that would give you the correct results.

    Examples are there in the installation software under the CSL folder.

    In case you are working with the USB stick C5515 and trying to write to the external NOR flash using DMA do let me know since I need help as well.

    Regards,

    AV.

  • 0 in reply to AV54983
    Expert 2635 points

    Hi Tommy,

    Refer to the NAND DMA example in the CSL: c55xx_csl\ccs_v3.3_examples\nand\example2. This example demonstrates how to configure DMA for accessing NAND through EMIF. Main thing is you need to configure proper DMA source/destination address based on the chip select of your external memory.

    Regards,

    Pratap