Hello, i want to use an external stable precise clock for measuring with the stm32 instead of the local crystal oszillator.

[URoso.1]

 I found only few ambiguous information how to connect the clock.

Are there any documents or shematics explaining the use of external clocks with the STM32?

Thanks in advance

Ulrich

[Chloe Meunier]

Hello Ulrich,

which STM32 MCU do you want to use?

For the clock, you can use internal clocks or to have more precision , an external quartz.

I think that what you want to use is named HSE in our technical documents (vs HSI for internal clock).

Does it helps you?

Regards

Chloé

[Muhammed Güler]

Here is an example link for the HSE oscillator.

from https://www.st.com/resource/en/schematic_pack/mb1364-h753zi-c01_schematic.pdf

there are different combinations in the reference designs. you can study reference designs and learn a lot

[URoso.1]

Hello Chloé,

thank you but i don't want to use a external quarz. Instead of the external quarz, i want to use an external clock source like a Rhubidium reference or an GPS stabilized quarz oszillator. At least a external low voltage TTL clock. For example the AVR controller can be used with an external TTL clock by feeding it into the input pin of the internal inverter for the quarz oszillator, but i did not found any documents for the STM32. I use the STM32F407 for this project.

Best regards

Ulrich

[URoso.1]

Hello Muhammed, thank you very much. That is what i am looking for.

Best regards

Ulrich

[TDK]

You can use a clock signal as the input to HSE by putting it in "HSE BYPASS" mode and piping the signal into OSC_IN as in the schematic above.

[waclawek.jan]

Which STM32?

 

Details for other STM32 may differ (e.g. whether the OSC_OUT pin may be used as GPIO or not).

JW

[URoso.1]

For this project a STM32F407.

Thank you very much. I have read a lot of the stm32 original documents and contributions from other user published in the www, but i have overseen this.