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Designing with STM32L496QGI6

Associate II

Hello Team,
We are planning to use the MCU STM32L496QGI6 for one of our products.
The HSE we are using is ECS-480-10-37B2-RWN-TR (48MHz crystal) and the value of the load capacitor is 20pF.
The board works well with HSI, but when we switched to HSE, even a GPIO was not toggling.
What could be the reason?
Looking for your reply

ST Employee

Hello @shibin , 

To check if the HSE is connecting properly, you can use an oscilloscope to measure the voltage across the crystal pins.


You can use the RCC_GetFlagStatus() function to check the status of the HSE. The function returns the status of the RCC flags, including the HSE ready flag. If the HSE is connected and stable, the HSE ready flag should be set (Bit 17 :RCC_CR_HSERDY: HSE oscillator clock ready).


To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

To measure performance you'd want to measure HSE exported via MCO (PA8) pin so as not to load the crystal.

If the crystal is not starting you'll need to review the components and layout, perhaps trying others, and checking if this STM32 has a "drive level" setting you can change. There's an app note on crystals for the STM32's

Check voltage scaling setting. Cited part says 10pF..

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