Hi,
This a follow-up question to our exchange last year regarding the proper way to achieve 0% or 100% duty cycle when using HRPWM enabled (this is on ePWM Type 4). As stated in the TRM, "the duty cycle must not fall within the restricted range".
Since there are several distinct features in the ePWM module which can affect the duty cycle by triggering edges, my new question concerns what exactly qualifies as "the duty cycle".
- Obviously using the CMPA/CMPB comparators is one such feature and the documentation clearly says that these register values cannot be within 3 cycles of the PRD or ZRO events.
- Conversely Nima Eskandari suggested the use of the AQCSFRC feature to achieve 0% or 100% duty cycle, so I assume the falling edge created by AQCSFRC is allowed to fall within 3 cycles of PRD or ZRO events?
- What about other events in the Action Qualifier module? Let's say I set up a signal with HRPWM in symmetric duty mode, with pulses centered on PRD (CAU = rising edge / CAD = falling edge). If during operation I reconfigure the module to CAU = rising edge / ZRO = falling edge it means the falling edge will occur at ZRO, in the middle of the forbidden range. Is this allowed or will it cause undefined behavior? The result would be the same as using AQCSFRC with RLDCSF = 0 but the code would be simpler since AQCTLA/AQCTLB are separate registers whereas AQCSFRC is a single register for both outputs.
Thanks and regards,
Pierre
