2019-03-25 12:27 PM
I cannot find any schematics, what kind of crystal. I want to connect 20 MHz. It seems it is as high as it can go. The datasheet does not say exactly what o connect.
Some of the STM have two pins to connect extearnal oscillator but this one has just one pin.
2019-03-25 01:34 PM
Connect to PH0-OSC_IN, leave PH1-OSC_OUT open.
2019-03-28 05:40 AM
Hello,
AN2867 application note can guide you in selecting the proper oscillator.
2019-03-28 06:05 AM
Should really review the Data Sheet
fHSE is specified as 48 MHz for Voltage Scaling Range 1, 26 MHz for Range 2
https://www.st.com/resource/en/datasheet/stm32l412k8.pdf
Parts using "CK_IN" expect an XO providing a CMOS level clock signal, ie TCXO
2019-03-28 06:07 AM
Not going to help if part doesn't bond out OSC_IN/OSC_OUT, and only provides PA0-CK_IN input.