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cross mob
Level 4
Level 4
First solution authored
I am using a XMC4500 for a 3-phase BLDC Motor control application. My Setup is taken from the application notes. I have the POSIF0 to sense the hall sensor Inputs and a CCU4 timer slice for the blanking and enabling the multi-channel update. I have the period match from the CCU8 slice to synchonize the multi-channel pattern update. This all works as expected.

As we need a high PWM frequency this gives a low PWM resolution. To increase the PWM Resolution I have enabled the PWM dithering. Dithering the period seems to give the most linear result. But now I have seen that the multi-channel patern synchronization does not work correctly. The first pulse of the PWM after the pattern change is not always the correct width.

The pattern synchronization is done with the period match event via service request 0. Why does the dithering have this negative effect on the service request? I could understand if the pulse was maybe one clock too short, but the pulse is anything from zero to the correct width.

Could someone please explain what is happening inside the CCU8 to cause this behaviour?
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