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Linas L
Senior
Apr 17, 2021 9:12 AM UTC
Solved

STM32L412 GPIO toggle from hardware without using dedicated timer as AF on that pin

Hello,

I run into problem for selecting TIM2 as my pwm output. As it turns out, it is only output capable. But I need to get processor independent 3kHz 50:50 PWM signal with no AF functional PWM.

Any simple idea how can I toggle with 50% 3kHz duty cycle this GPIO? (PA15 on STM32L412C8)

I Am thinking of using DMA, just have no idea how to do that, since I can't use ODR register,I have multiple pins that should not change, and with BRR BSRR, well, it is two address, so what ? Do ping pong DMA with single transfer and circular buffer ?

Any ideas are welcome :)

This topic has been closed for replies.
Linas L
Linas LBest answer
Senior
Apr 17, 2021 12:45 PM UTC

Hi,

I found the problem, I was looking at LPTIM2 instead of TIM2

No problems in this case :) Thank you all !

3 replies

Uwe Bonnes
Chief
Apr 17, 2021 9:22 AM UTC

PA15 is TIM2_CH1and can do PWM . All other solutions wll give you at least Jitteror even missing cycles.

Linas L
Linas LAuthorBest answer
Senior
Apr 17, 2021 12:45 PM UTC

Hi,

I found the problem, I was looking at LPTIM2 instead of TIM2

No problems in this case :) Thank you all !

Piranha
Principal III
Apr 17, 2021 11:34 AM UTC

First, like Uwe already said...

Second, read what a BSRR register is. At least read it's name!