Posted on June 29, 2015 at 20:43Hello everyone,
Excuse me for creating a discussion similar to one that I have already created, but I decided to give it a last try, because I could really use some help.
What I want to do precisely is this:
Timer1 (Produces 3 PWM pulses at Ch1,2 and 3)-> 50KHz
Timer2 (Used to trigger ADC in tripple mode)->200KHz (Not a standard number, I need to be able to change it to various frequencies)
I want to define some offset and then trigger Timer 2 periodically in every period of Timer1, get 4 samples and then stop. (The 4 samples is not a standard number, it depends on the frequency)
Attached you will find an oscilloscope image of what I need exactly. I did it, but through software, which is not stable. I would like to implement it through hardware, but unfortunately it seems a lot harder than I thought.
One idea I had was to use Timer1 Channel 4 and trigger Timer2 at the desired time offset, but unfortunately I am probably missing something because I can't make it work.
Another idea is by using a third Timer, which will trigger Timer2 after the time offset. However I don't know how to synchronize the third timer exactly with Timer 1. Even if I enable him in Timer1 Interrupt, there will be some clocks delay. Moreover again I will be based on interrupt, which I would like to avoid if possible.
( I maybe could use a 4th in one pulse mode, to trigger Timer 1 and 3 at the beginnign simultaneously, but I think there must be an simpler way to do that, without using 4 timers)
And finally, even if I do that, is there any way to stop after a specific number of ADC captures?
Thank you in advance.
Regards,
Pantelis
#adc #stm32f4 #timer #sync
