Hi! I have a problem with a chart. It plots the variables but most of the time their values seem to be 0 (what is not correct). I'm using stm32f103re with st-link/v2

[NZask.1]

[NZask.1]

I've tried dicovery board, and it plots just what i expect.

[NZask.1 · Accepted solution]

Guys, I found what caused this strange behavior, it was

__WFI();

[Piranha]

Sleep

It is not a requirement for the processor hardware to drain any pending memory activity before suspending execution to enter a sleep mode. Therefore, software has to handle this by adding barrier instructions if the sleep mode used could affect data transfer. A DSB should be used to ensure that there are no outstanding memory transactions prior to executing the WFI or WFE instruction.

http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dai0321a/BIHHFHJB.html

[stephane.legargeant]

When the processor is in WFI, the tool is not able anymore to access the memory : when the tool reads data, the probe returns 0 and not the real value.

So it is not possible to get the data when MCU uses WFI instruction.