The MUX settings should be the same, but are not because these last settings freezed my M0 twice.
Also you did not comment on the observations on the stencilled Word doc., where you can see that some parts of the sketch are not operative: this should surely point to relevant differences.
Apart from this, please let me know if your sketch on your M0 works as described in your post, because on this M0, some parts REALLY DO NOTHING, as per my previous stencilled Word doc.
Bt the way, where you from?
I ordered two Zero's in France last friday, march 11 and should be here any time now. Will advise.
REG_TCC0_CCB3 = 1351; // TCC0 CCB3 - 50% duty cycle on digtital pin 7 (D7)while(TCC0->SYNCBUSY.bit.CCB3);