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Difference between HSE and HSE Bypass

Question asked by sunside on Feb 21, 2015
Latest reply on Feb 22, 2015 by Clive One
After some hardware struggles with my new STM32F3 disco board I finally got it running correctly and at high speed. I was wondering, however, that there seems to be no difference between HSE and HSE bypass mode, as both settings result in clocking the system with 72 MHz.

Sadly, I am unable to find some clear explanation in the reference manual. What is the difference between the two settings, technically?

Is it just that in bypass mode, an external clock is provided to OSC_IN (with OSC_OUT being free for GPIO adventures) while in regular HSE mode a real oscillator needs to be present? Is it correct to assume that bypass mode would then be the "best" setting for the discovery board (a regular version with one oscillator for the F103 and none on X2)?

Regards,
Markus

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