STM32WL LPUART1 for both Bootloader and AT Commands

[Hamady]

Hello i Have a question about the STM32WL5MOC.

I need to be able to use the bootlader of the WL and in the same UART line use the AT Command.

But it seems that LPUART1 that is the only way to use AT Command Application is not used in the bootloader.

Do you have any idea to have both functionality 

Thanks

[Andrew Neil]

The System Bootloader and your application code are mutually exclusive:

• While in the System Bootloader, your application code is not running;
• While running your application code, the System Bootloader is not active.

The choice between System Bootloader and your application code is controlled by the BOOT0 pin.

PS:

Application note AN2606, STM32 microcontroller system memory boot mode describes the System Bootloader.

You can also jump to the System Bootloader from your application code:

https://community.st.com/t5/stm32-mcus/how-to-jump-to-system-bootloader-from-application-code-on-stm32/ta-p/49424

[Hamady]

@Andrew Neil 

Thanks for the info 

What i mean is that i can only afford one UART line and be able to use bootloader

Thanks

[Andrew Neil]

Yes, the System Bootloader is restricted to use only the specified interfaces; so, as shown in your  table, only USART1 or 2 - not the LPUART.

But that doesn't stop you using a custom bootloader on any interface you choose ...

https://community.st.com/t5/stm32-mcus-products/how-can-i-use-an-esp32-to-update-the-firmware-of-an-stm32-from/m-p/696331/highlight/true#M254868

[STTwo-32 · Accepted solution]

Hello @Hamady 

As said @Andrew Neil, the Open bootloader is always an option. But if you are using the LPUART on your trace code and you just want to have only one line (two Pins TX/RX), you can use the LPUART for your application code and the USART2 for the bootloader since the USART2 and the LPUART1 are both using the same pins (PA2 and PA3 as TX and RX) and they don't work simultaneously as said @Andrew Neil . 

Best Regards.

STTwo-32