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Compiler/TMS320F280049M: What is the clock frequency of the EPWM module?

yun long
Intellectual 270 points
Part Number: TMS320F280049M


Tool/software: TI C/C++ Compiler

 TRM of TMS320F280049M  on page 1491 says that  EPWMCLK is equal to SYSCLKOUT / 2. Since the clock frequency of TMS320F280049M is 100MHz, that is EPWMCLK is 50MHz(20ns). and when HSPCLKDIV and CLKDIVis set by default (CLKDIV=0,HSPCLKDIV=1), so TBCLK is equal to 25MHz(40ns),but This is conflict with Table 15-10 on page.Who could help me answer doubts? Thanks!

  • 0
    TI__Genius 15260 points
    Hi Jari,

    The PWM clock is configurable. You just must make sure that the PWM clock is not greater than 100 MHz. The note that you are referencing on pg 1491 is actually not applicable for this device. This is a bug in the documentation, and I will submit to have it corrected. On this device EPWMCLK will default to SYSCLK/1.

    The HSPCLKDIV and CLKDIV fields can be used to further divide the time base clock down if needed by your application. Most users will leave these at their default values.

    Regards,
    Kris
  • 0 in reply to Kris Parrent
    Intellectual 270 points

    Hi Kris

    Thank you for your reply！I still have a question to consult you: When I  read the module of  Deadband,  The data Sheet  provides reference on how to configure the DBRED,DBFED register  on  page 1528. And the recommended  configuration is below.  As you said,  When EPWMCLK is equal to 100MHz(10ns), so if  DBRED,DBFED  register  is configured to 5, Why  the deadband time  not  equal to 0.05us but 0.06us in the first column.  So is DBReD,DBFED equal to 10, the same situation.  I wonder whether  this table still exists  some errors, If so,  could you give me some advice.  Thank you very much!


  • 0 in reply to yun long
    TI__Genius 15260 points

    Hi Jari,

    It appears the values in the table are calculated based on an 80 MHz (12.5 ns) EPWMCLK. It looks like we updated the header to say 100 MHz but didn't get the updated values into the table. I'll make sure to get this updated as well. Thanks for all of your great feedback!

    The correct values are as you suggested for the first column- 10ns*value in the deadband register.

    Regards,

    Kris