Nucleo-144 STM32H755ZI vs STM32F767ZI

[lserrnt]

Hey there,

I am facing a problem with the clocks on the STM32H755ZI. When I let a timer run at 50 kHz I get only smt. like 49.92 kHz out of it with sigma = 13 Hz. So there is at any frequency a steady offset of -1.2% and a sigma deviation of 0.03%. I have chosen as HSE the Crystal/Ceramic Resonator and the APB2 of the timer runs at 200 kHz.

With the Nucleo 144 STM32F767ZI I get for similar settings basically 0% frequency offset and sigma deviation of only 0.0003%. So I am wondering what has changed between these discovery boards

H755:

https://www.st.com/en/evaluation-tools/nucleo-h755zi-q.html

F767:

https://www.st.com/en/evaluation-tools/nucleo-f767zi.html

they both have this X4 crystal at 25.000 MHz and several others.

So do you see any way how I can achieve a higher frequency stability? Or what I might have to change in CubeIDE to activate a more accurate crystal on the H755 board? 

Thanks a lot for any help 🙂

[lserrnt]

I will recheck in future with an external crystal as X2. Thank you for your help 🙂

[KevinNapier]

hello.How can i program the STLINK to output 8.33MHz? 

program in here?

thx.

Kevin

[Peter BENSCH]

@KevinNapier For 8.33MHz, you must reprogramme the ST-LINK with the corresponding option during the ST-LINK firmware update.

[MasterT]

[KevinNapier]

Compris. Merci beaucoup.