• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 84 subscribers
  • Views 1065 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F2837xD ePWM Module

Jeremias Reith
Prodigy 130 points

Other Parts Discussed in Thread: TMS320F28377D, CONTROLSUITE

Hi,

I am working with the TMS320F28377D Control Card and wrote Firmware Drivers for several ePWM Modules, that are going to be used with our next digital Controller.

In principle, everything worked fine except the following issues:

1) ePWM Modules seem to be clocked not by SYSCLKOUT (200MHz) but with SYSCLKOUT / 2 Frequency. All frequency divider inside the ePWM Module are disabled ( /1). Is this correct? Will this be changed with further chip revisions?

2) Feature "AUTOCONV" and HRPWM works fine with ePWM1-7, but ePWM8 cannot enable AUTOCONV Bit. Will this be changed with further chip revisions?

3) Datasheet notes that there are 16 HRPWM Outputs available (ePWM 1-8, A&B), but I couldn't find CMPBHR Register at all!?

I am really looking forward to further comments on these issues...

Many thanks,

Jeremias Reith

  • 0
    TI__Guru 57255 points

    Jeremias,

    I will answer question (1) and pass (2)/(3) on to other members of my team.

    1) Your understanding is correct.  The divider that you mention can actually be disabled, but the PWM is designed to be clocked at no more than 100MHz as per the datasheet.  As you may know, using the device outside of the datasheet limitation is not recommended and we do not guarantee proper behavior.

    We do not currently have any plans to change this on future F2837xD device revisions.


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Prodigy 130 points

    Brett,

    okay that's definitely no problem for our design, we can work with this without any problems.

    I just wanted to be sure that I am doing nothing wrong with internal clocks...

    I am looking forward to your member's answers on issue 2) and 3) ...

    Thank you,

    Jeremias

  • 0 in reply to Jeremias Reith
    TI__Guru 57255 points

    Hi Jeremias,

    Update:

    We are looking into (2).

    (3) is a software bug.  We confirm this is an issue and we will resolve it in a future version of controlSUITE.  Thank you for reporting this!


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    TI__Genius 15260 points

    Jeremias,

    For the problem with Autoconvert on EPWM8, can you give further details and a code snippet of how you are trying to perform this?  I have tested the HRPWM output on EPWM8 and am not seeing any issues.  I would recommend using the code from the hrpwm_duty_sfo_v8 ControlSUITE example as a starting place.

    Thanks,

    Kris 

  • 0 in reply to Kris Parrent
    Prodigy 130 points

    Hi,

    many thanks for your support on issue (1) and (2) so far.

    Regarding issue (3) with HRPWM and AutoConv functionality I can reproduce the behaviour using hrpwm_duty_sfo example as well.

    Obviously it is not possible to enable Auto-Conversion on ePWM Channels 2,4,6,8 (see attached screenshot).

    All writes of 1 to Auto-Convert Register (CPU Writes or Debugger) Writes are not successful....

    Best regards,

    Jeremias

  • 0 in reply to Jeremias Reith
    TI__Genius 15260 points

    Jeremias,

    Just to confirm the issue you are seeing here- are you only having trouble enabling AUTOCONV in EPWM8 or in all of the even modules (2/4/6/8)?  The original post said just EPWM8, but the screenshot appears to show the issue with all even EPWM modules.

    If it is the latter, then this is a known issue with the earlier revisions of silicon.  Please see the errata document for more details- the specific one is pasted below.

    This issue has already been fixed in the latest revision of silicon.

    Kris

  • 0 in reply to Kris Parrent
    Prodigy 130 points

    Hi Kris,

    that's it. I recognized this issue only for ePWM8 first, as this is the only even ePWM Output using HRPWM in my design. Afterwards I saw this issue with all even channels....

    But many thanks for this hint, that's exactly how my hardware revision works. Therefore the workaround on my side is clear and solves the problem. Great!

    Many thanks....

    Jeremias