RTC not working on STM32L073RZ

Amir Chaudhary

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Sep 4, 2019, 5:53:27 AM9/4/19

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We have made 500 PCB's with STM32L073RZ and 150 have issue in starting the RTC.

We have used the recommended 32.768Khz but its not working for the 150.

We have tried changing the recommended 32.768Khz with the cylindrical crystal it worked but when I tested after an hour it was not working.

If I heat the RTC with the blower it works and later it stops working. It works when we touch on the PCB with hands touched on the crystal and its caps.

I have tested changing the crystal its 4.3pF caps but not working.

I have soldered the 8Mhz crystal body to ground, changed the LSE crystal with cylindrical crystal and grounded it body but it works temporarily and later stops working.

I have been programming the PCB with mbed OS and everytime it shows "Cannot initialize RTC with LSE" error.

The PCB layout is also attached.

Please guide.

rtc mypcb layout.PNG

rtc issuie.PNG

mohammadreza sakhavar

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Sep 4, 2019, 5:56:37 AM9/4/19

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So it’s not related on easy rtc ,
Please check some shime

Amir Chaudhary

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Sep 4, 2019, 5:59:10 AM9/4/19

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It is related to RTC (Real Time Clock)

mohammadreza sakhavar

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Sep 4, 2019, 6:51:27 AM9/4/19

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Hey bud , you got a mistake , this a framework that communicate not time clock , this is (Real Time Communication) to send data betweens browsers.

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