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5 years ago.
STM32L476 LSE startup issues
Has anyone verified that the STM32L476 Discovery or Nucleo is starting the LSE correctly? I have tested it on 3 boards, a Nucleo, a Discovery Board, and a custom board with a STM32L476RG and none of them will start the LSE into oscillation. Using the same code on a STM32L152 Nucleo will start it up correctly. See the attached scope captures.
The code looks like it tries to start the LSE, but will revert to the LSI if can not start. This is where my problem is, I want to use the RTC for wake up timing and the LSI is not very accurate.
STM32L476 Nucleo STM32L476 Discovery Board STM32L152 Nucleo
5 years ago.
Extend the LSE timeout to 500mS. There is an update due very soon to correct the RTC reset issue on POR and nRST and includes this change.
If you want to use RTC for deep sleep / wake up see here:
I am using this and works well. It also does not interfere with RTC time functions.
One BIG problem is the Interrupt function with the L476, in a nutshell it doesn't work resulting in all sorts of problems.