TMS320F28377S: Up-Down count and external synchronization

Andrew Barnett

Part Number: TMS320F28377S

I am implementing a phase-shifted-full-bridge converter that uses the PWM registers in up-down count mode. I need to synchronize the PWM output to an external signal. The sync signal is twice the desired switching frequency with 50% duty cycle. Is there some means of toggling the count direction each time a rising (or falling) edge of the incoming sync signal is received? The first rising edge would place the counter in up-count mode and the next rising edge would place the counter in down-count mode, and so on.

Thanks in advance for any insight.

over 4 years ago

0 Marlyn Rosales Castaneda20 over 4 years ago

TI__Mastermind 25850 points

Hi Andrew,

Please take a look at the PHSDIR bit of the TBCTL register. It specifies the direction of the time-base counter after a synchronization event (to either start counting up or down). You will have to control the logic yourself though to recognize how many rising edges have passed and to what you need to set the bit to.

Best Regards,

Marlyn

0 Andrew Barnett over 4 years ago in reply to Marlyn Rosales Castaneda20

Intellectual 870 points

Thanks Marlyn, this is taking me down the correct path.

I have a few more questions but would like to discuss privately. Can we please initiate a separate private discussion?

Thanks,

Andy B

0 Marlyn Rosales Castaneda20 over 4 years ago in reply to Andrew Barnett

TI__Mastermind 25850 points

Hi Andrew,

I have sent you a friend request. Please accept and we can discuss through messaging.

Best Regards,

Marlyn

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TMS320F28377S: Up-Down count and external synchronization