stm32f410 ADC monitor a sinewave

Hello all,

i am working on a project which implies the control of a BLDC motor in 3 phases.

For this type of motor the switching of the phases must be sync with monitoring the 'back-emf' signal from the unpowerd phase.

My question would be, what is the common practice to measure a zero falling edge signal at 30 degreese after the sinewave is passing down trough 0. A ADC triggerd by a fixed timer value?

I dont have very much experience with ADC's in tandem with timers