Check RTC LSE(External Xtal, 32.768kHz) mode

Dependencies:   mbed CheckRTC

Please refer follow links.
My notebook
http://developer.mbed.org/users/kenjiArai/notebook/nucleo-series-clock-structure-and-xtal-oscillation/
Q&A for RTC Xtal
http://developer.mbed.org/questions/4531/RTC-External-Crystal-Nucleo/

CheckRTC.lib

Committer:
kenjiArai
Date:
2015-05-16
Revision:
4:56a0cbad89b0
Parent:
3:921a09e41147

File content as of revision 4:56a0cbad89b0:

http://developer.mbed.org/users/kenjiArai/code/CheckRTC/#babcde30190d