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Can ADS8556 be connected to 28335 by DMA?

xiaochen liu
Prodigy 20 points
Other Parts Discussed in Thread: ADS8556, TMS320F28335

Hello everyone

First thank you focusing on my question.

I am designing a data acquisition system using ADS8556 as analog to digital converter.

In this system TMS320F28335 is used as main  processor.

I want to transfer adc results to 28335 by DMA, but the BUSY/INT signal is only 1.8ns short, it can not be catch by 28335.

So i want to ask engineers "can ADS8556 transfer data to 28335 using DMA module"?

    

  • 0
    TI__Guru**** 180941 points

    Hi Xiaochen,

    For the ADS8556, the BUSY/INT should be something on the order of 64ns wide.  Depending on how you have the ADS8556 device configured, the shortest pulse on the BUSY/INT output is one conversion clock wide, which should be plenty of time to trigger an interrupt in the TMS320F28335.

    Regardless, the DSC has various timers which can be set up to trigger the CONVST through the DMA controller.  Since the conversion time is known, you can trigger the CONVST and then read data without the need to service an XINT.  In parallel mode, the minimum configuration for this type of setup is shown in Figure 43 on page 35 of the datasheet.  You could also configure the McBSP of the TMS320F28335 to do DMA transfers as well if you want to run the ADS8556 in serial mode.

  • 0 in reply to Tom Hendrick
    Prodigy 20 points

    Hi Tom,

    Thanks for your suggestions, I will do some test then I will write down the results here.

    Thanks for all sharings.

     

    Best Regards

    LodgureLiu