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Using LSE for RTC on a STM32F4DISCOVERY board.

Question asked by arnal.jean_louis on Feb 24, 2013
Latest reply on Jul 2, 2013 by belomutskiy.andrey
Hello everyone.

As many may have noticed, the STM32F4 discovery boards comes with an unfitted OSC32 crystal (X3) & biasing caps (C16 & C27).

Did anyone ever tried to provide  her/his the board with those missing components.


I tried to solder a 32.768Hz T6 crystal, salvage from a functionnal digital clock, along with 15pF caps, but no matter what, the LSERY flag never get set even though LSEON is.
Of course, I didn't provide VBAT any external supply, since it's bridged to VDD through R26, but the LSE is bound to be powered by VDD due to the internal reset circuitry anyway.
Still, no oscillation on the crystal's pins... strange.

Did I neglect some hardware configuration ?

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