TMDSDCDCLEDKIT: ePWM1 to ePWM2 synchronization error

Hi Alberto,

Thank you for providing detailed description of the issue. I believe it is quite clear what is happening. 

We expect that the ePWM1A (SEPIC) and ePWM2A or ePWM2B signals (MASTER module that manages the first two strings of LEDs) are synchronized. This does not happen, just look at the screenshots of the oscilloscope below.

The reason expected behavior is not seen is because PWM1 and PWM2 are both set-up as Masters. There are two ways to ensure that PWM1 and PWM2 will be perfectly synchronized. 

1. You can leave PWM1 and PWM2 as Masters and follow the procedure outlined in the user guide to disable TBCLKSYNC bit at the start of initialization routine, configure all PWM registers, and then enable TBCLKSYNC bit. This will make sure that all PWM clocks are started at the same time. This way as long as PWM1 and PWM2 frequencies are integral multiples of each other, and fixed, these PWMs will always be in sync.

2. The other option is to use PWM1 for driving the 1st LED string and PWM2 for driving the SEPIC switch. You can now make PWM1 the Master and PWM2, 3, 4.. as the slaves. PWM1 syncout will sync PWM2 time-base (use a TBPHS value of 0 or 2 for PWM2). As PWM1 is 20kHz, this will only happen every 5th PWM2 cycle. Again, as long as these two frequencies are integral multiples of each other, you won't have to worry about anything else. PWM2 syncout should just pass-through the syncin input from PWM1 to PWM3. PWM3, 4... can now still be synced to PWM1 with desired phase shifts.

I hope this helps.

Hrishi

Hrishi,

Thanks for your support.
Both solutions are not working.
In particular, first is not solving the issue and second is not feasible because GPIO00 Is used for SEPIC .
Can you kindly provide your feedback?

Thanks and regards
Alberto