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turn-on MCU at different voltage than turn-off (BOR on-the-fly change?)

Associate III


I'm using an STM32WB15CC MCU. I want it to turn on (get out of reset) only when the VDD voltage gets up to, say, 2.8V, but not turn off via Brown-Out Reset (BOR) until the voltage drops to the minimum working voltage of ~1.7V. What's the easiest way to do that?

My first thought: the BOR voltage is generally set in the option bytes which are non-volatile. However, is it possible to "temporarily" change the BOR setpoint, i.e. without changing the non-volatile option bytes? If this is possible, then I can do what I want: I'll set the option bytes to a 2.8V BOR threshold but have my first line of code change it *temporarily* to 1.7V. This way it is held in reset until the voltage gets to 2.8V but doesn't turn off until it drops below 1.7V - but when it does turn off, it will only turn on again  at 2.8V because I did not touch the non-volatile BOR setting.

is the above method possible? if yes, then how do I change the BOR temporarily?  if not, then can you suggest another approach to get the same end result?