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Original question:

TIDM-02002: Switching from a CPU to another

TIDM-02002: Implementing blanking on TMS320F28377D

Lorenzo Lutti
Intellectual 665 points
Part Number: TIDM-02002
Other Parts Discussed in Thread: TMS320F28377D, TMS320F280049

Hello, as written in a previous thread a couple weeks ago, I'm porting the TIDM-02002 code from TMS320F280049 to TMS320F28377D. The porting was quite straightforward, except for the synchronous rectification functionality configured on CLLLC_HAL_setupSynchronousRectificationAction(). This function makes use of the EPWMBLANK signal, configured through COMPDACCTL.BLANKEN and COMPDACCTL.BLANKSOURCE. Apparently this feature is not supported at all by the 377D.

I have a couple of questions:

1) How does the lack of this feature impact on the overall synchronous rectification function? Is this just an improvement for better noise rejection, or a fundamental part of the function?

2) Are there workarounds with the 377D to achieve similar results?

Thank you, and sorry if the questions are very generic. I am still in the process to fully understand the code associated with this function, and I have to admit that I find it quite a challenging task.

L.

  • +1
    TI__Mastermind 42195 points

    This bit gives the ability to extend the blanking time

    . 

    it is not explicitly required depending on how long you would like to blank.

    F2837x devices have the standard blanking capability. F2838x devices are an updated version of F2837x devices which have the feature discussed here.

    Regards,
    Cody 

  • 0 in reply to Cody Watkins
    Intellectual 665 points

    Thank you Cody. The description of this feature is quite laconic, basically it is limited at the line that you've highlighted.

    What I did not notice before is the note 1 in the TMS320F2837xD technical reference manual (spruhm8i), figure 15-54:

    "On the F2837x/F2807x family of devices, EPWMxBLANK does not go to the CMPSS".

    Considering that this is the TMS320F2837xD reference manual, the note 1 is always true and the diagram is quite misleading.

    L.

  • 0 in reply to Lorenzo Lutti
    TI__Mastermind 42195 points
    Lorenzo Lutti said:
    Considering that this is the TMS320F2837xD reference manual, the note 1 is always true and the diagram is quite misleading.

    Agreed this is confusing. It is an artifact of an attempt to reduce developmental overhead though the reuse of documentation.

    Regards,
    Cody