What determines if a peripheral is enabled during startup?

[D.Heink]

Hi,

i am working on a Project right now where i need to send some data via LoRa. I'm using a STM32WL55 and i had some trouble with the radio setup, so to check the basic functionality of my radioi rebuilt the SUBGHZ_Tx_Mode example for my board and compared the actual example running on a Nucleo-WL55JC1 with my rebuild running on my board.

The MXsetup is identical for both.

I noticed that even before i start the code, i can see in the debugger, that on the nucleo the RFBUSYS Bit is set and on my board it isn't.

Reading the documentation, i found out that if the radio resets, the RFBUSYS flag goes high, so it makes sense that at the very start the RFBUSYS flag is set on the Nucleo, as the whole board does a power on reset.

But why doesn't the radio on my board perform a reset (or at least set the RFBUSYS bit)?

How can there be a difference if no line of code has been executed yet and the Mx setup is the same?

I'm completely lost on this issue, so any help is greatly apprechiated.

[D.Heink]

Turns out i forgot to connect the VFBSMPS and the VDDRF1V55 pins, so the radio didn't get any power.

And no power -> no power on restet