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RTC frozen (M41T93) on my STM32L052

Question asked by Fred on Jan 13, 2016
Latest reply on Jan 13, 2016 by FTITI.Walid

I try to use the RTC M41T93 with a microcontroler STM32L052. I use the SPI1 for the communication. It seems to work well as I am able to read the time, to write the time and some registers.

The problem is that when the power supply falls, the RTC is supposed to continue running on the battery (CR2032). But when the power comes back and the microcontroler restart, the time is the one when the power supply fell.
For exemple : if the power supply falls at 10:13:00, and I wait 5 minutes, when I restart the power supply, the time is still 10:13:00 (and few more secondes), and it continues incrementing then.

The starting sequence on the microcontroler is :
wait 5s
wait 4s
wait 100ms

Is there something I forget ?

I thank you in advance.