F373 current in Stop Mode too large

[fiim]

Posted on April 19, 2013 at 16:49

VDDC should be 5uA, AVDD should be 2uA. But I have 500uA.  I tried to enter in the stop mode before and immediately after the system_init, without any initialization settings. Tried also to do pins IN, FLOAT, AF. Stop and Standby. WFI and WFE. Trying to run the RTC, and without it - the result is the same >500uA. Where the deuce? By the way, with L15x had no such problems.

[fiim]

Posted on April 20, 2013 at 14:59

I found the reason. You need to fully de-initialize not only the ports(PINs), but also all the peripherals(ADC, USB, MAL...). Thus, the output of the slip mode is quite a long one: you need to again re-initialize all. It is sad. May, before the stop, it is worth to remember the state of all registers used by the periphery, and when leaving the stop, restore the values, without calling the initialization function?-

[jj2]

Posted on April 20, 2013 at 23:02

Noted - then read w/interest - thank you.

Seems a rather severe change from your other device (assuming you did not go thru same routine there) - and that is concerning. 

Are you able to repeat these findings on a 2nd MCU - to insure this isn't single chip (or board) aberration?

[fiim]

Posted on April 30, 2013 at 10:55

I think this is a feature of the device. All the same, stm32L15x is specially designed for small consumption. If he had the 16-bit ADC, then it would be perfect device)). It would be good for F37x examples, where when disconnected from the USB-line device would change to stop(5uA wRTC), and when you connect -back from stop(wADC preConfig!).At least I do it short & beautifully could not.

[frankmeyer9]

Posted on April 30, 2013 at 11:40

I think this is a feature of the device. All the same, stm32L15x is specially designed for small consumption. If he had the 16-bit ADC, then it would be perfect device)).

 

Why not taking an external ADC ?

MCU-internal ADCs are usually cheaper, but otherwise don't really gain from their close proximity to digital circuitry. And with some extra effort one could have true differencial inputs.

[fiim]

Posted on April 30, 2013 at 13:35

I agree, but for my purposes it is enough such a simple 16-bit ADC, and a 12-bit is not enough)) And if he did was useless, then why would it have done? And the price of 5$ or 5+5 also plays a role)