HSE oscillator not running on NUCLEO-H753ZI board

[Ondrej1]

Hello,

I use NUCLEO-H753ZI with processor STM32H753ZI. In deafault settings there is not mounted external oscillator, but I need application where it's mounted. So I added oscillator 25Mhz (same type as is described in schematic for board) and capacitors. Then I try to run FatFs_USBDISK_Standlone (intended for STM32H743 - STM32H743I-EVAL). If I switch on internal oscillator (HSI) example is running. But if I use external oscillator (default settings of project) the frequency is not correct. I verified it by test led blink with timer (the measured frequency is about 3 times smaller then calculated). Also if I try to measure oscillator frequncy (on C70 - see schematic for board) i can see signal with 8Mhz frequency on oscilloscope (the waveform is similar to a charging and discharging of capacitor ~ triangle waveform).

Does anyone know what may be incorrect in my settings?

Thank you for response!

[SofLit]

Hello,

Did you solder the solder bridges SB3 and SB4? (not soldered by default):

Also use MCO function to output the HSE frequency on one of the dedicated pins instead of probing the crystal signal on its pad.

[Ondrej1]

Thank you for your advice.

Yes, I did. Bridges are soldered.

I enabled MCO1 output and set 23th bit of RCC->CFGR register (on the output is hse_ck signal), MCO1 precaler is switched off. The signal on dedicated pin (PA8) has also 8MHz frequency.

[SofLit]

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I enabled MCO1 output and set 23th bit of RCC->CFGR register (on the output is hse_ck signal), 

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Try first to use CubeMx for your first tests if you plan to optimize the FW later.

Try to generate a project with the attached .ioc file.

[Ondrej1 · Accepted solution]

Thank you for help.

I just found the problem. There is also bridge SB45 that must be desoldered, otherwise its driven from ST link.