HSE BYPASS clock not working on stm32H750

[Jzhua]

I'am using 26M oscillator on stm32H750VB device, it's not working on rev V, but same configure is work fine on rev Y.

[Jzhua]

I tried to change the oscillator from a different supplier, but there is no improvement，HSERDY cannot be ready

[Imen.D · Accepted solution]

Hello @Jzhua​ ,

Make sure to use a HSE which is listed in AN2867 as compatible with STM32H7 series.

 

Please mark my answer as best by clicking on the "Select as Best" button if it fully solved your issue. This will help other users find this solution more quickly.

Imen

[YChangting]

Hi.Jzhua,

I encountered the same question as you.I used a NDK 38.4MHz TCXO，set HSE bypass mode,HSE waiting timeout was resulted on Rev V,it didn't work.But on Rev Y,all is OK.

Have you sovled this question? I supposed this is a bug on Rev V.If you sovled this qustion,please tell me the method.My email is bitstar@163.com,waiting your answer.

Regards.

Yu Changting

[Jzhua]

Just replace an oscillator with a larger output amplitude.

[YChangting]

Thank very much. Under your hint,I found the OSCin of rev V is a standard I/O pin on HSE bypass mode.But Almost TCXO's outputs have 0.8V Vpp and 0.9V VOH. Tthere is no TCXO being compatible with Rev V.To solve this problem,an extra circuit must be designed.