make sure you configure these registers inside of
EALLOW;
// make secure register changes after EALLOW
EDIS;
the set-up of your ePWM Trip Zone is correct
EPwm4Regs.TZSEL.bit.OSHT1 = 1; //enable TZ1 for OSHT
for the action on the event we usualy do it like this
EPwm4Regs.TZCTL.bit.TZA = TZ_FORCE_LO; // EPWMxA will go low
EPwm4Regs.TZCTL.bit.TZB = TZ_FORCE_LO; // EPWMxB will go low
