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STM32L4 Run power not constant.

ITama
Associate

Hello I am using a STM32L476,

I am having issues with the power consumption, Every time it resets, the power consumption is different as in +-500 uA but I have seen as much as +-1.0 mA.

I am using the MSI at 48 Mhz. After initializing the clocks, I initialize all my GPIOs inputs, outputs, alternate functions, (none of them digital floating of course). Then use the SPI to set some external devices to sleep.

Then, right after everything is supposed to be initialized. I trap the MCU in a while(1) loop.

I want to know the power consumption when the processor is awake.

In my scenario, it is hovering around 12.5 mA. BUT:

The problem is if I reset, either from watchdog, power cycle or reset pin. the power consumption will not be NOT the same. I have seen it around as low as 12.0 mA or as high as 13.0 mA.

Note: once the new power consumption shows up, it is very stable and does not wobble around. (this should indicate there are no floating inputs).

I am still trying multiple things here, but I can'.t seem to get it consistent...

Another thing to note: if I go to sleep in Stop 2, i always get rock solid 20 uA. which means the rest of my components are sleeping as expected.

Can anyone give me a clue on what to start looking for? I am running out of ideas.

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