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TMS320F280021: eQEP questions

HS FAE Germany
Mastermind 30485 points
Part Number: TMS320F280021

Hello,
customer wants to us the eQEP for different encoder projects.

Additional to the eQEP features he needs:
- 2x CMP position-compare (can this be solved with the CLB)?
- count on 1, 2 or 4 edges (configureable) in quadrature count mode
- count on 1 or 2 edges (configureable) in direction count mode 

Regards, Holger

  • 0
    TI__Genius 15385 points

    Hi Holger,

    Does customer want to use above features (Quadrature & Direction Count mode) using CLB? 

    Best Regards,

    Nirav

  • 0 in reply to Nirav Ginwala
    TI__Mastermind 30485 points

    Hello Nirav,

    he wants to use the eQEP but needs additional features (see above). May be these features can only be fulfilled in combination of eQEP+CLB.

    Regards, Holger

  • 0 in reply to HS FAE Germany
    TI__Genius 15385 points

    Hi Holger,

    Understood, what kind of encoder does customer plan to use? and what does the QEP signals looks like? 

    Do they want configurability to generate QCLK on Rising/Falling or both edges on eQEPA/eQEPB signals?

    It will be good to understand the details to give more specific answer, using CLB we can build logic for post processing as desired. We can also use QMA block inside eQEP, not sure if customer have already looked into it?

    Best Regards,

    Nirav

  • 0 in reply to Nirav Ginwala
    TI__Mastermind 30485 points

    Hello Nirav,
    I think for the different inputs detections you can achieve this with the CLB or QMA:
    - count on 1, 2 or 4 edges (configureable) in quadrature count mode
    - count on 1 or 2 edges (configureable) in direction count mode 

    But I don't have any idea for the 2nd CMP. Let me explain what he wants to do:

    - load the position counter with an offset (shaft position) eg. QPOSCNT.=4000
    - monitor/detect a spefic turn of the shaft in both direction. QPOSCMP1=3000, QPOSCMP2=5000

    So request is for QPOSCMP2. I don't see how to do this with CLB because there no signal path from eQEP to CLB.

    Regards, Holger

  • +1 in reply to HS FAE Germany
    TI__Genius 15385 points

    Hi Holger,

    QEP signals from GPIO can also be routed to CLB, which can be used to implement Quadrature Count/Direction count mode, also QPOSCMP2 can be implemented in CLB.

    Best Regards,

    Nirav