HRTIM G474RE

[PJFIXER]

Hello everyone ,

I have a Project where i wish to have a 8Mhz PWM pulse. For this i use the HRTIM timer at 4.9Ghz with a period of 600

I have my PWM output but it seems that i can't set 0% duty cycle ? in fact duty cycle seems to not work between 0% & 16% (96) .

I have read differents subjects where people are  expericiencing the same issue .

https://community.st.com/t5/stm32-mcus-products/stm32f334-hrtim-with-bad-behavior/td-p/409531 

https://stackoverflow.com/questions/69572777/stm32-hrtim-pwm-only-work-when-master-compare-is-70ns 

it seems that its just not doable with HRTIM on ST MCUs..

Could someone confirm that having 8mhz PWM with 0% to 100% duty cycle is not achievable with ST MCUs 

best regards

[Issamos]

Hello @PJFIXER 

The best way to do this is to test it using all possible configurations.

Best regards.

II

[Yassine EL KHOURASSANI]

Hello, 

Indeed, I confirm this rule for HRTIM:

rm0440-stm32g4: "The high-resolution behavior is not supported for pulses narrower than 3 tHRTIM periods"

For an HRTIM running at the max frequency: (5.44Ghz/96)*3 = 170Mhz

This is normal while PADs in MCUs could not support a very high frequencies, except PADs with PHYs, but this means allocating specific PADs for timer, without alternating which is a limitation for a general purpose MCU.

Best regards.