on newer boards, 2 or 3 years ago, there is a LSE installed.
Please check:
http://www.st.com/content/ccc/resource/ ... 105823.pdf
There are three possible default configurations of the LSE depending on the version of the
STM32 Nucleo board hardware.
The board version MB1136 C-01 or MB1136 C-02 is mentioned on the sticker placed on the
bottom side of the PCB.
The board marking MB1136 C-01 corresponds to a board configured as LSE not used.
The board marking MB1136 C-02 (or higher) corresponds to a board configured with
on-board 32 kHz oscillator.
The board marking MB1136 C-03 (or higher) corresponds to a board using new LSE crystal
(ABS25) and C26, C31 and C32 value update.
Only small changes need to activate them.