stm32wb55 reset pin

[dungeonlords789]

Hello!

It will be interesting to know about reset system inside stm32wb55. I have got not casual reset schematic.

Where InA is digital Isolators IC input. I also tested without this IC and result is the same. Rpu is build-in stm32wb55 pull up resistor. R13 is 360 Ohms.

stm32wb55 doesnt't start! I am looking reset pin using oscilloscope

At some moment voltage drop! It looks strange, but after 500 us there is 3.3 V on reset pin but stm32wb55 doesnt't start!

I change R13 to 100 Ohms and look

Hill looks strange but stm32wb55 works!

Why MCU doesn't works with R13 360 Ohms?

[Scott Löhr]

@dungeonlords789​ - I am not a h/w guy, but if you don't know the answer to your own question, then why would you attempt to design a reset circuit for the STM32WB that is anything other than exactly what the ST designers created for their Nucleo dev board?

[dungeonlords789]

Because I have not enough pins.

What about top post?

@Imen Ezzine​