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The problem of the Kinetis RTC time

Question asked by fukefeng on Jul 2, 2014
Latest reply on Sep 19, 2014 by fukefeng

I use the kinetis MK70FN1M0VMJ15 MCU for more than two years,and we use the mqx system.  but now we found that the RTC sometimes don't work well,it would reset to 1970 years. and most times it happened on the POWER ON.  our schematic diagram is just same as the official schematic diagram(the only difference is the diode).  The time is very important for us,does anyone found the same problem or has same suggestions for me. my schematic diagram is under blow:


the official schematic diagram is use the diode of BAT54C, and I use the 1N4148. Can this the problem? I measure the diode forward voltage is 0.3v, the VBATD voltage maybe enough for the mcu.

very thanks for give me some suggestion.