How to change NUCLEO-G431KB PWM duty cycle

[Jason_fx]

I use the PWM output example code of STM32CubeIDE,

how do I modify the duty cycle of the PWM, I can't find a way to modify it

[Stassen.C]

Hello Jason,

You can simply change the PULSE_VALUE in the main.h

Regards,
Stassen

[Issamos]

Hello @Jason_fx 

TIMx channels duty cycle = (TIMx_CCR1/ (TIMx_ARR + 1))*100.

 

You can change the values off TIMx_CCR1 and TIMx_ARR to modify the duty cycle value.

Best regards.

II

[Jason_fx]

Hi Stassen, 

Thanks for your reply.

But I have a question,

I find this code but I can't understand how to change the PULSE_VALUE,

example code is output PWM has a 90% duty cycle, if change 50% duty cycle how to set the PULSE_VALUE?

[mxo]

hello @Jason_fx 

you can simply set "duty * counter-base-period" to "Compare Register" just like followings..

 where V_TIM_Cbase is defined in configration as below.

hope this could help

regards

[Jason_fx]

Hi MXO,

I can't understand how to join your code,
The definitions provided by your code and example code seem to be different.

[mxo]

hello, @Jason_fx

off course join the codes into your main() or some applicable place by yourself.

and, if the Counter Period in your project is for example "999" (=1000-1), I mean V_TIM_Cbase = 1000,

then it should be refered in the code which I show you.

if your sample code is as below,   

  PulseVal = (uint32_t)(vfPdt * (PERIOD_VALUE + 1));

would be OK, but well.. I don't like it.

Is it OK now?

regards.

[Jason_fx]

Hi @mxo 

I can't find the ___HAL_TIM_SET_COMPARE function on the PWMOutput sample code

I tried changing #define PULSE1_VALUE (uint32_t)(1000 / 2) to #define PULSE1_VALUE (uint32_t)(50000 / 1) and it outputs 76% but I don't understand code work logic.

[mxo]

hello @Jason_fx 

>I can't find the ___HAL_TIM_SET_COMPARE function on the PWMOutput sample code

you can find in stm32??xx_hal_tim.h. (?? = depends on your project, I guess)

One important thing that duty must be 0 ~ 1 (or can say 0 ~ 100%).

is your sample project 'TIM_PWMOutput', right?

#define PULSE1_VALUE (uint32_t)(50000 / 1)  .. means over 100% duty.

since the base period is 1000 in that sample project, pulse value should be 0 ~ 1000, or result is unexpected.

TIM_PWMOutput project only shows set duty (=pulse value) at configuration time.

better to find some other samples to understand function, then this can be enough to talk, I think.

regards.