STM32L4R9 power consumption figures in stopModes on Discovery board don't match the electrical characteristics

[arouaux]

Hi, with my team we are currently investigating the low power features of the STM32L4R9 MCU on a DISCOVERY board. 

We are measuring the current consumption on JP1, plugging an external amperemeter between pins 3 and 2.

We would like to check the datasheet figures while entering in the different stopModes (0, 1 and 2) with this very simple code:

int main(void)
{
	__HAL_RCC_PWR_CLK_ENABLE();
        HAL_PWREx_EnterSTOP0Mode(PWR_STOPENTRY_WFE);
        //HAL_PWREx_EnterSTOP1Mode(PWR_STOPENTRY_WFE);
        //HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFE);
}

We observe that whatever stop mode we use, we get the same current consumption which is around 0.3mA.

This figure is far from the electrical characteristics where in stop2 we should have something around 10uA.

We are wondering if the MCU correctly shutdown the main regulator in stop1 and stop2? Does anyone know how we can check this?

We are also maybe missing some preliminary configurations, does anyone have any advice or piece of code to achieve better consumption figures for that chip on that board?

One other thing is that on that board, all power supply pins are tied together. Could this power consumption come a wrongly configured pads?

Any advices would be welcome!

Thanks

Regards

Anthony

[MM..1]

Primary your code is bad, use code from examples in firmware repository.

Secondary dont enable debug in low power modes...

[arouaux · Accepted solution]

Hi MM..1,

Thank you for your quick and efficient answer and for your advices about my debugging coding style.

You are right, the debug was enabled. My mistake was that I thought that it will be disabled after a reset of the board. Indeed it was not.

After a power down of the board, I can see better current consumption values, in the different sleep modes.

Regards

Anthony