How to generate TRGO exactly at the midpoint of PWM ON-time in Center-Aligned PWM Mode 2?
Hello,
I'm using STM32F103RB and have configured TIM1 Channel 1/2/3 as PWM Generation CH1/2/3 in Center-Aligned Mode 2.
The clock source is internal (HSI = 8 MHz), and the APB2 timer clock is set to 64 MHz.
I configured PSC = 1 and ARR = 1599 to produce a 20 kHz PWM.
My goal is to trigger ADC at the exact midpoint of the PWM ON-time, which in Center-Aligned PWM Mode 2 should correspond to the point where CNT reaches ARR.
To do this, I tried setting Trigger Event Selection (TRGO) to Update Event, but I suspect that the update event happens both when CNT = 0 and CNT = ARR.
If so, it wouldn't guarantee that the trigger is generated only at the center of the ON pulse, which is my intended sampling point for BEMF.
My questions are:
Does Update Event in Center-Aligned Mode 2 occur both at CNT = 0 and CNT = ARR?
If so, what is the best way to configure TRGO so that ADC is triggered only when CNT = ARR, i.e., the center of PWM ON-time?
Would using Output Compare (OCxREF) as the TRGO source and setting CCRx = ARR be a better approach?
Any clarification would be very helpful.
Thank you!