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TMS320F28075: TBCLKSYNC to sync PWM9 and PWM10

Howard Zou
Genius 12365 points
Part Number: TMS320F28075

Hi,

my customer is using F28075, and they need to configure PWM1-8 72kHz, PWM9-12 60kHz.

Due to the limitation of the EPWMxSYNCI, they can't sync PWM10 to PWM9, they can only sync PWM10 to PWM7.

So they would like to try to TBCLKSYNC to sync PWM10 with PWM9.

Can we guarantee that PWM10 and PWM9 are always synced with TBCLKSYNC? Since TBCLKSYNC will only take effect one time at the beginning.

Is it possible that there will be some error(for example one or two clock mismatch) when the PWM runs for a long time?

  • 0
    TI__Mastermind 23350 points

    Hi Howard,

    Is EPWM 10 and 9 configured the same way? Do you have any synchronization involving EPWM 7 or 8?

    Best Regards,

    Marlyn

  • 0 in reply to Marlyn Rosales Castaneda20
    TI__Genius 12365 points

    Hi,

    we would like to configure EPWM10 and EPWM9 180° phase shift. No synchronization involving EPWM7 or 8.

    Since there is no SYNCOUT for EPWM9, there is only SYNCOUT signal routing to EPWM10 SYNCIN signal, so we cannot use EPWMxSYNCI to sync EPWM9 and EPWM10.

    So we intend to use TBCLKSYNC, and we configure both EPWM9 and EPWM10 updown count, and then we configure opposite action for CAU (EPWM9 flip to high, EPWM10 flip to low for example) and CAD.

    Can we guarantee that PWM10 and PWM9 are always synced with TBCLKSYNC? Since TBCLKSYNC will only take effect one time at the beginning.

  • +1 in reply to Howard Zou
    TI__Guru 52020 points

    IF you have the same PERIOD, and the same EPWM CLOCK DIVIDERS, and then set BOTH EPWM10 and EPWM9 to start by setting TBCLKSYNC, they will always be in sync.