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CCS/TMS320F28379D: Example "eqep_pos_speed_cpu01" index signal not resetting theta_raw

George B.
Prodigy 30 points
Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hello there,

I own a LaunchPad-XL TMS320F28379D and I have imported "eqep_pos_speed_cpu01" example from C2000Ware. I have no problems building and running the project. Absolutely no changes have been made to the code. I am using graph to read the values of theta_raw which is practically the value of QPOSCNT register. However I don't notice a reset when the index pulse comes out of the GPIO4. I have tested the connections with an oscilloscope an everything seems right. I am attaching a screenshot of the graph. Shouldn't theta_raw reset to 0 when the index pulse comes out? Should I change the value of an eqep register to force reset on index? Thanks for your time.

 

  • 0
    TI__Genius 15385 points
    Hi George,

    Are you providing index event on GPIO04? How are you doing it? Inside the code, it only drives it low? Can you scope out GPIO4?

    Also, if you are using C2000Ware example code, GPIO23 is configured as the eQEPI (Index signal), so in order to reset QPOSCNT you need to toggle GPIO23 externally and not GPIO4. Only if you want to toggle Index event through the code you can output the toggle on GPIO4 and externally connect GPIO4 to GPIO23 inorder to reset the QPOSCNT.


    Regards,
    Nirav