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Using LSE for RTC on a STM32F4DISCOVERY board.

arnaljl2
Associate II
Posted on February 24, 2013 at 02:29

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 ?

#stm32f4discovery-rtc-lse-crystal
10 REPLIES 10
arro239
Associate III
Posted on July 02, 2013 at 22:13

Thank you clive1, you are 90% of manpower on this forum!