AnsweredAssumed Answered

STM32L4 LSI and power-down sequance

Question asked by shachar y on Jan 14, 2018

Hello,
In our Evaluation board of the STM32L486QG we encounter in strange behavior of the MCU.
When the power supply turned off and on quickly we saw that sometimes the MCU start to getting in to loops of IWDG.
We are using the LSI as the IWDG source and we saw that when it happens the frequency of the LSI is ~ 48KHz and not as it should be ~ 32KHz.
We are not sure that this simptom is the problem, and we will apprciate your help.
Another thing that we noticed is that if the MCU voltage supply did not discharge to 0V but to around 0.7V the registers in the backup domain does not clearing.
We saw that for example LSERDY bit does not clear.
Is there any power-down and power-up sequance that we need to follow?

Thanks in advanced,
Shachar

Outcomes