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TMS320F28075x Sync signal for ePWM

Kengo Furuya
Expert 7650 points

Hello, now I'm checking TRM SPRUHM9B of TMS320F2807x.

http://www.tij.co.jp/jp/lit/ug/spruhm9b/spruhm9b.pdf

In Figure 15-8. Time-Base Counter Synchronization Scheme 4, SYNC signal is connected between EPWM1 to EPWM3, but EPWM4 is not connected from EWPM3 by SYNC signal.

On the other hands, in Figure 13-65. Control of Dual 3-Phase Inverter Stages as Is Commonly Used in Motor Control, SYNC signal is connected to EWPM6 from EWPM1.

Can SYNC signal of EPWM on F2807x connect to all of EPWM module? Or, only connect in 3 module(EPWM1 to EPWM3, and EPWM4 to EPWM6..)?

I think all of EPWM module can be connected by SYNC signal like the other Piccolo series, but let me confirm if F2807x also can be used as the same use case.

Regards,

Furuya

  • 0
    TI__Genius 15260 points
    Hi Furuya,

    Figure 13-7 Time Base Counter Synchronization Scheme 4 is the architectural implementation. The SYNCO of EPWM3 does not directly connect with EPWM4. There may be ways to get around this, such as using the Digital Compare Submodule to create a sync. I understand how Figure 13-65 is misleading and will submit for the figure to be modified.

    Thanks,

    Kris
  • 0 in reply to Kris Parrent
    TI__Expert 7650 points
    Hi Kris, sorry for the response.
    I understand the SYNCO is connected directly between EPWM3 and EWPM4. But, it means F28075 does not have flexibility to sync easily for each EPWM module as compared with previous Piccolo device. Could you provide any sample code to synchronize between EWPM3 and 4 by Digital Compare Submodule?

    Regards,
    Furuya
  • 0 in reply to Kengo Furuya
    TI__Genius 15260 points

    Furuya,

    Sure- I will work on some sample code. It will likely be 1-2 weeks before delivery.

    The basic idea of it is to use the Input X-Bar set to the pin which outputs the EPWM3A or B signal (whichever you want to sync to) and route that to EPWM4's DC submodule to create a sync event. You will then use the TBPHS register as necessary to adjust for the delay of the propagation (value will vary slightly with SYSCLK) and any phase shift.

    Regards,

    Kris

  • 0 in reply to Kris Parrent
    TI__Expert 7650 points
    Hi Kris,

    Could you provide some sample code? It would be helpful for me.

    Regards,
    Furuya
  • 0 in reply to Kengo Furuya
    Expert 2015 points

    Hi Furuya,

    EALLOW;

    CpuSysRegs.PCLKCR0.bit.TBCLKSYNC = 0;

    EDIS;

    config all ePWMs

    EALLOW;

    CpuSysRegs.PCLKCR0.bit.TBCLKSYNC = 1;

    EDIS;

    This wll synchronise all ePWMs.

  • 0 in reply to Prakash Kumar Thulasi Kumar
    TI__Expert 7650 points
    Hi Kumar,

    I'm talking about Time-Base Counter Synchronization, not Time-Base Clock Synchronization. I think PWM3 and PWM4 cannot do the Time-Base Counter Synchronization by your description.

    Regards,
    Furuya