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RTC works in one board does not in other board

Question asked by Mosi Yaghi on Oct 11, 2016
Latest reply on Oct 16, 2016 by Pavel Hudeček

I have a pretty weird problem with the LPC1768 RTC for couple of months. 

See I have two different boards with LPC1768 and both have external mounted 32768Hz crystal and the same program. One board is a custom designed board while the other is a starter board with almost nothing on it (just power and Jtag). 

Now the problem is that RTC works in starter board while it does not work in the other board. I mean it's obvious that it's not counting and incrementing time. 

LPC1768 is working fine and there is nothing wrong with it. The 32768Hz crystal is mounted almost near to the controller and the capacitors are mounted as well. I even soldered another board but it didn't work either !! 

 

That's why I decided to mount an external RTC like DS3231 but it has it's own problems and since I want to use Deep Sleep mode I figured to use RTC interrupt to wake up the controller in specific times (Is there other ways to do this?)

 

Now do you guys have some ideas why it's not working in some boards while does in others? 

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