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TMS320F28335: Controlling pins with XINTF and DMA

Edvin Hjortland
Prodigy 45 points
Part Number: TMS320F28335

Tool/software:

Hi,

I have an application where I would like to control GPIO output pins through the DMA. It is my understanding that the GPIO set/clear control registers can not be accessed by the DMA. Is there a way to setup the XINTF interface for this purpose. 

What I am trying to setup is a timer that triggers the DMA to update the output pins with data from a predefined data table in RAM. Can this be achieved by the XINTF module?

Regards,

Edvin 

  • 0
    TI__Guru** 113725 points

    Edvin,

    Sorry for late reply. 

    Edvin Hjortland said:
    What I am trying to setup is a timer that triggers the DMA to update the output pins with data from a predefined data table in RAM. Can this be achieved by the XINTF module?

    Yes, this should be possible. 

    Vivek Singh

  • 0 in reply to Vivek Singh
    Prodigy 45 points

    Thank you for your reply.

    I'm struggling to set this up. Given that the XINTF interface is primarily a memory interface, I don't see how I can make the GPIOs hold their values until the next DMA transfer updates the GPIOs to a new values. It seems that the GPIOs will only hold the desired values during the write strobe period. Am I missing something here? Do you have any pointers on how to achieve this?

    Regards,

    Edvin

  • 0 in reply to Edvin Hjortland
    TI__Guru** 113725 points
    Edvin Hjortland said:
    It seems that the GPIOs will only hold the desired values during the write strobe period. Am I missing something here? Do you have any pointers on how to achieve this?

    You are correct. You can change the EMIF timing to make these strobe timing bigger but after that these pins will go to the default value. 

    Vivek Singh