Nulceo WB55 Example not waking up from stop mode from LPUART

Manoj1 · ‎2025-06-16

I have referred to the Example project "LPUART_WakeUpFromStop_Init". Configured an LP-UART in interrupt mode with a baud rate of 9600, Stop bit 1, Parity None, and enabled the HSI clock source for it. When the device enters the stop mode, try to send a character to wake it. But it is not all waking up.

We need to try this on Nulceo WB55 evaluation board. Once it works, we need to use it on our product which uses the uC STM32WB55VGQ.

Andrew Neil · ‎2025-06-16

@Manoj1 wrote:
We need to (sic?) try this on Nulceo WB55

Do you mean you are trying this on a Nucleo WB55 ?

Are you certain that it actually does enter STOP mode?

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

STTwo-32 · ‎2025-06-16

Hello @Manoj1

Have you tested the example "LPUART_WakeUpFromStop_Init" as it is, if it is working fine, you shoudl check the impact of your changes on the code. Also, you may check if the Code enter stop mode and if HSI16 oscillator is forced ON even in Stop mode.

Best Regards.

STTwo-32

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