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STM32WB55 external clocks(32.768KHz, 38MHz) not working

brian.kwon12
Associate II

Hello All

I have a cutom board. I am working on STM32WB55VGQ6(BGA129).
2 crystals(32.768KHz, 38MHz) output waves are not coming.
I checked waveform by using an oscilloscope and OSC-IN/OUT pins are ground level(0V)
Voltage conditions all 3.3V : VDD, VDDUSB, VDDRF, VDDA, VDDSMPS
Crystal part# : FW384WFIN1, AGS05-32.768KHZ-6T
Expers please help me.

17 REPLIES 17
AScha.3
Chief III

did you set the lse+hse in Cube ?  and flash this program then ?

AScha3_0-1689411608703.png

otherwise cpu running on internal clock only.

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KKIM.6
Senior II

I'm using WB55 but WB55 use 32 MHz, Not 38 MHz. you need to check spec whether 38 MHz is correct.

You can check whether clock is correctly implanted to microcontroller following this example that company provided.

https://www.youtube.com/watch?v=qNJR9vL1D0c

Hi KKIM
Thank you for fast response.
STM32WB55 supports 64MHz.
I'd changed 16MHz OSC it still not working

Hi AScha.3
Thank you for response.
I'd tried connect to my board with STM32cube but STM32cube can not access my board.

MM..1
Chief III

StLink pinout? What is your cube ? IDE or Programmer sw?

so this is first problem, you have to care about.

without loading a program - no external clocks running.

+ connect with...stlinkV2 ? or how to..? and boot pin at gnd ? or try bootloader ?

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Hi MM

Thank you for response.

I'm using STM32CubeIDE(ver 1.13) and microUSB 5pin cable, not use STlink.

Hi AScha.3

Thank you for your interest.

I'm not using STlink, connect with microUSB 5pin cable.

Boot pin is connected at GND.

Your choiced bootloader load isnt native suppoerted in IDE. You need handle load sw manualy or over script. Too you cant debug with this setup. Why you choice this?

MM1_0-1689611158158.png