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TMS320F28076: How to use simultaneously Endat/Biss and PTO functions?

Part Number: TMS320F28076

Hello All,

My customer is inserting the encoder repetition using PTO on the new project with the DSP F28076 and reading the Texas forum it seems that it is not possible to use this function with the absolute encoders endat and biss because the libraries use the same resources.

In particular the ePwm4 and the CLB.

From the thread, at the end of 2017, it seems to understand that a version of the library was foreseen that integrates these two functions, but then I found no more trace about this: http://e2e.ti.com/support/microcontrollers/c2000/f/171/t/608775?tisearch=e2e-sitesearch&keymatch=pulsegen 


Can you please tell me if the case has been addressed and solved, or how the Endat / Biss and PTO functions can be used simultaneously on F28076.

Many Thanks,

Antonio

  • Hi Antonio,

    We are currently working on a tool to configure CLB - that will be available for customers in 3Q19. Using this tool, customers can develop/simulate and configure CLB to perform the functions of their choice. We would also be providing some examples with the tool on how to configure different functions.
    We have moved away from library based model and instead enable customers to develop functions on their own.

  • Hello All,

    Just to give customer an idea of what can be done concurrently on a given device please find below how many CLB tiles each encoder standard typically takes.

    So in the current libraries:

    Many Thanks,

    Antonio

  • Hello All,

    Our target is:

    To implement on '076' CLBs concurrently the management of one input encoder and one output encoder repetition/simulation (see table).

     

     

    Encoder Input

    Encoder Output

    1

    Incremental Digital

    Repetition

    2

    Incremental Sinus

    Repetition

    3

    Absolute Sinus + Incremental Sinus

    Repetition

    4

    Absolute Digital + Incremental Sinus (EnDat, BiSS, …)

    Repetition

    5

    Absolute Full Digital (EnDat, BiSS, …)

    Simulation

     

    We have successfully tested CLB libraries for point 1, 2 and 3.

    The point 4 operate correctly but we cannot manage the encoder input and the repetition lines at the same time (is impossible to load concurrently two CLB libraries).

    The point 5 operate correctly but the simulation library function is not available.

     

    The TI team wrote last year that all our requirements could be satisfied with the CLBs tool (except for the EnDat 2.2 full).

    >>> Do you confirm this?

    >>> The release date for the CLBs tools is planned for 3Q19?

    >>> To speed things up, can TI team share us software libraries or code about encoder repetition/simulation?

     

     Maurizio

     

  • Hi,

    Maurizio Rusconi said:
    The point 4 operate correctly but we cannot manage the encoder input and the repetition lines at the same time (is impossible to load concurrently two CLB libraries).


    CLB libraries, for these functions, currently are designed to work independently - not at the same time.
    If you are attempting to use multiple functions like 2 Absolute encoders at the same time - libraries will not work as they use same resources and hardware.

    Maurizio Rusconi said:

    The TI team wrote last year that all our requirements could be satisfied with the CLBs tool (except for the EnDat 2.2 full).

    >>> Do you confirm this?

    >>> The release date for the CLBs tools is planned for 3Q19?

    >>> To speed things up, can TI team share us software libraries or code about encoder repetition/simulation?



    Note that there are only 4 CLB tiles, and connected resources are limited as shown in the library user guide of each of these functions.
    CLB tool currently are scheduled to release in 3Q19.
    We are currently focused on tool development/release and enabling customers to develop solutions on their own - no closed source library development is planned.

  • Hi,

    I would like to specify that we have not to use two encoders at the same time but one absolute encoder and the PTO qepdiv function.

    If I understand you say that:

    Point 4: it not possible because absolute encoder library (Endat or Biss) and PTO library share the same resources, CLB and other, and cannot be loaded together.

    Point 5: simulation function is not available.

    My questions are:

    1. Did I understand it right?

    2. Apart CLB which are the others concurrent resources? Reading the library user guide it seems that there are not other shared resources between encoder and PTO Qepdiv. Encoders use PWM4 and PTO Qepdiv uses PWM 1 and PWM2.

    3.When the CLB tool will be available, will it be possible to develop these functions (encoder and PTO) running together? And it will be possible to develop the encoder simulation? 

     

    Thank you

    Maurizio Rusconi

     

  • Hi,

    Maurizio Rusconi said:
    1. Did I understand it right?


    You are correct - These combination functions are not currently available.

    Maurizio Rusconi said:
    Apart CLB which are the others concurrent resources? Reading the library user guide it seems that there are not other shared resources between encoder and PTO Qepdiv. Encoders use PWM4 and PTO Qepdiv uses PWM 1 and PWM2.


    There could be a conflict in the CLB instances used. Though there is no conflict in the PWM output GPIOs used for these functions, in some cases.

    Maurizio Rusconi said:
    3.When the CLB tool will be available, will it be possible to develop these functions (encoder and PTO) running together? And it will be possible to develop the encoder simulation? 


    Yes. But some combinations like EnDat22 + PTO (QepDiv) may not be possible as there are not enough CLB resources.
    Note the number of CLB tiles used for each function in the table above. And note that there are only 4 CLB tiles - so the maximum functions you can develop will depend on the available resources and the resources consumed by corresponding functions.

  • Hi, I'm closing this thread as we are discussing over call/email offline.