External crystal not oscillating

[MDeva.1]

Hello,

I have custom board. I am working on STM32H7 controller. We use the external crystal of 25Mhz. But when we use that external oscillator using the HSE ,it doesn't provide the clock to controller. Why these happening. Can you please help me

[Imen.D]

Hello @MDeva.1​ 

Is STLink disconnected/connected?

I advise you to check the board schematics and User manual.

Have a look also at this AN2867 Application note Oscillator design guide for STM8AF/AL/S, STM32 MCUs and MPUs.

Imen

[MDeva.1]

I am using the STM32CUBEProgrammer for programming. The STLINK is connected to Board and PC.

[itsrabbit]

Hello @MDeva.1​ ,

Where do you use your external clock? For example, you choose your clock as HSE in clock configuration, but as Internal Clock in where you need it (TIM clock source etc.) right?

Are you sure that you run your tasks after Init and clock config functions?

[MDeva.1]

I am sharing the snap of my configuration part in these I enable the USB and GPIO . If any thing is wrong please tell me

[itsrabbit]

I was trying to ask, what do you use your external clock for? If you are using it for timer interrupt is timer clock source correct?

[Javier1]

every time this happened to me the issue was the XTAL capacitors were too high.(wrong values placed by the production team)

[ONadr.1]

The crystal could be broken or, more probably, has different parameters, than MCU need. You can try conect a paralel rezistor to crystal, about 1Mohm, or different type of crystall. You should read the AN2867 to know, how to choose a crystal according to its parameter, as ST employee proposed in the first answer.

[CYANG.1]

Hi

You may refer to ST STM32H7 tools boards on ST website and choose same parameters parts of crystal circuit on these boards. ​