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Associate II
January 9, 2024
Question

PWM Frequency generated

  • January 9, 2024
  • 3 replies
  • 1750 views

Hi,

i am working on STM32F302R8Tx and i would like to have a  490 Hz PWM on Timer15 Channel2, 

attached are my configuration and my code, when i measure it , i become 491,13..Hz. what can I do to get the exact 490Hz? 

Any  Suggestions?? 

thank you!!!

Jess32_0-1704784722767.png

Clockkonfiguration.PNG

Pinout Konfiguration.PNG

 

 

 

 

 

 

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3 replies

AScha.3
Super User
January 9, 2024

Hi,

you clock at 64MHz , 

so -> 64M / 130 = 492,3kHz

divide by counter (arr) : (1005-1) -> 489,9Hz (closest you can get here)

---

If you set 64M / 131  , arr (997-1) , then 490,02 Hz is possible.

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waclawek.jan
Super User
January 9, 2024

Also, HSI is not a precise primary clock source (see datasheet for HSI specification), so there will always be some error introduced by that fact.

JW

Jess32Author
Associate II
January 9, 2024

okay, thank you for your answers!!!!!