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Original question:
TMS320F280039C: PWMxA and PWMxB with phase shift by deadband module
Tool/software:
".... Phase shifting B-channel with respect to the A-channel: When PWMxB is derived from PWMxA using the DEDB_MODE bit and by delaying rising edge and falling edge by the phase shift amount. When the duty cycle value on PWMxA is less than this phase shift amount, PWMxA’s falling edge has precedence over the delayed rising edge for PWMxB. It is recommended to make sure the duty cycle value of the current waveform fed to the dead-band module is greater than the required phase shift amount."
Is "Phase shifting B-channel" functional when High-resolution deadband is enabled?
Hi Echo,
Thanks for clarifying. Yes, this should be possible. What issue are you seeing with your outputs? It would help if you provided some diagram of the settings/initializations you are applying to the EPWM if you are able.
Some initial questions - which count mode are you using? Are you using up-down count mode? Is half-cycle clocking enabled? Also note that the DBRED and DBFED values must be greater than 3 to use high-resolution deadband.
To debug this, I would suggest backtracking and slowly building your waveform. I would typically start by first disabling HR capability and any DeadBand and confirm you have the desired raw waveform. If you have already done so (or once you have done so), add the deadband submodule to obtain your desired nonHR output. Can you confirm that the below is what you are targeting and is what is reflected in the registers during runtime?
Once you have this set, you need to apply HR deadband. What are your settings for the HRCFG2 register?
And are you writing to the deadband DBRED/DBFED registers in a single 32-bit write?
Best Regards,
Allison
