Nucleo - STM32L412RB-P: How to measure IDD only through STM32 Microcontroller?

[Ypinh.1]

I have generated minimal code using cubeMX that i enter stop2 mode and never wake up.

i added some functions to decrease power consumption and tried to combine between them in order to see how the idd measurements changes.

among the functions:

killing the debugger

disable systick interrupt

disable RTC

deinit all ios and thier ports

disabling all ios clocks

define ios as analog pull down

disabling HCLK,PCLK1,PCLK2,HSI CLK,MSI CLK,LSE CLK

no matter what, i always see above 150uA while in the datasheet i see that the MCU should support arround 1uA in STOP2 mode.

In the board datasheet UM2206 Rev 3 about the IDD measurement it is written:

that the IDD measurement is used to measure the STM32 microcontroller, the level shifter and the SMPS consumptions.

i would like to know how can i measure only the MCU current consumption and see really arround 1uA when on STOP2 mode?

quote from the board datasheet:

"The jumper JP6, labeled IDD, is used to measure the STM32 microcontroller, the level shifter and the SMPS consumptions (depending on solder-bridge configuration), by removing the jumper and by connecting a multimeter:

• Jumper ON: directly powered (default)

• Jumper OFF: a multimeter or an external 3.3 V power source must be connected to

measure the consumption

Note: The STM32 Nucleo-64-P board LEDs are connected before the jumper. The LED consumptions do not impact the V

DD_MCU

power measurement."

Thanks

[Bertrand DENIS]

Hello,

There is a high probability that some IOs are not correctly settled. I saw you set all IOs as pull-down but if there is an external pull-up you will see a power consumption.

Check the schematics and set each IO accordingly.

Bertrand

[Ypinh.1]

Thanks for your reply,

I looked on the schematic and didnt see any io that is connected to an external pull up resistor.

anyway i defined even all the ios as GPIO_MODE_ANALOG_ADC_CONTROL pulldown, pullup and as nopull only to catch big differences but didnt notice any huge different. it was all around the range 147uA - 153uA and took some time untill it gets stable, so for me it means that the influence of the analog inputs can be minor according to my total current consumption, am i miss something?

i think that i dont measure only the MCU and therefore i see power consumption of the other components (level shifter and the SMPS) if its right, then i dont know what should i do to take them off the measurement.

*i connect the board to power via usb cable ST LINK.

*in addition i have NUCLEO-L476RG and in this board i got the expected 1.1uA using the similar code and i defined the ios as analog NOPULL

[Piranha]

DBGMCU->CR = 0; // Disable debug and trace in low-power modes

Do this before entering low-power mode.

[Ypinh.1 · Accepted solution]

I succeed to solve the issue, i dont understand excactly why it works.

the solution was to move JP7 jumper to pins 2 and 3 instead of pins 1 and 2 that was set by default.

even not need to do that much in the code before entering stop2 mode and get current conusmption that arround 0.8uA to 5uA.

all the things i have tried to do before entering stop2 mode, decrease or increase the consumption in minory way.

so, it works, but it is not stable while im in stop2 mode.

instead of getting only 1uA i get sometime jumps between 0.8uA to 5uA.

[Ypinh.1]

Thanks for reply, ill test it and see how it influence