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TMS320F28377D: Fast data transfer from DMA to CLA

Brian Wang0
Expert 5350 points
Part Number: TMS320F28377D


Hi team,

Here is one question about fast data transfer between DMA and CLA.

My customer is using DMA to get the result of ADC(@400kHz), but their control loop runs in CLA(@100Khz). And the the control loop needs the ADC sampling result.

Our question is:

1. Can DMA directly access to CLA Data RAM? If it is possible, then we could leverage DMA to transfer ADC result directly to CLA data ram, then no additional operation would be needed for CLA to use ADC result.

2. If the answer is no, what is the recommended way to implement DMA and CLA for such a scenario?

Regards,

Brian

  • 0
    TI__Expert 4610 points

    Brian,

    Regarding your question 1, it is not possible on TMS320F28377D device.

    You can directly access the ADC results from CLA. That would be the simplest way to implement the control loop using CLA & ADC

    Regards,
    Praveen

    Note: If my post answers your query, please click "This resolved my issue" button.

  • 0
    TI__Guru 55700 points

    Brian,

    CLA has access to highlighted RAM memory shown below. Which memory are you talking about when you say CLA data RAM? We have CLA data ROM not CLA data RAM.

    We don't have any memory location which has both CLA / DMA access at the same time. Please check Pg 182. Table6-1. C28xMemoryMap for more details www.ti.com/.../tms320f28379d.pdf

    As Praveen suggested, CLA can access ADC result register directly.

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    TI__Expert 5350 points

    Hi team,

    Thanks for the quick reply. 

    Yes we are aware of the idea that CLA could be used to access CLA. But the problem is ADC ISR and control ISR would overlap. 

    Another idea is that ADC ISR runs in CPU1 CLA and control ISR runs in CPU2 CLA. But according to our understanding, these 2 CLA also cannot share access to a common RAM. In this way, the data flow would be CLA1(ADC Sampling)->CPU1->CPU2->CLA2(control SIR). And this is obviously not what we hope to achieve.

    Regards,

    Brian

  • 0 in reply to Brian Wang0
    TI__Expert 4610 points

    Brian,

    You can also keep the ADC ISR running from CPU and consume the ADC result data inside the CPU1 CLA task.

    Regards,
    Praveen

    Note: If my post answers your query, please click "This resolved my issue" button.