How to power a Nucleo board from battery

[GStou]

I have a combination of a Nucleo64 (STM32L053) with an X-NUCLEO-S2868AI S2-LP board.

The program on it works fine, now I want to test to power from a battery. 3.6V

I took out the jumpers that connect the processor to the ST-Link section, only the uart remains connected. (SWO and nRST are also still connected)

Somehow I see strange things: there is power reaching the system, not enough to get things functional but there is a signal on the line

the strange thing is that the process runs, I have information that makes sense on the debug uart line, but no messages get emitted by the S2-LP, althow I see no error messages.

[GStou]

I don't get the issue I faced.

Using a new battery solved the issue of not receiving messages.

Testing the low voltage mode (1.8V) works perfect, this is way below the previous voltage level with the used battery the resulted in failing communication.

I use the 3.3V Arduino pin to inject the power in the Nucleo boards.