STM32F411 - Not getting lowest current consumption when putting device into standby

bm · ‎2016-12-21

Posted on December 21, 2016 at 17:23

So I want my device to go into standby mode to run on the lowest power mode possible. Unfortunately, when measuring the current it does not drop below 360�A and I have no clue why...

This is my HSI setup:

configure_system_clock(void)

{

RCC_OscInitTypeDef RCC_OscInitStruct;

RCC_ClkInitTypeDef RCC_ClkInitStruct;

RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;

__HAL_RCC_PWR_CLK_ENABLE();

__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;

RCC_OscInitStruct.HSIState = RCC_HSI_ON;

RCC_OscInitStruct.HSICalibrationValue = 16;

RCC_OscInitStruct.LSIState = RCC_LSI_OFF;

RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;

RCC_OscInitStruct.PLL.PLLM = 8;

RCC_OscInitStruct.PLL.PLLN = 192;

RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;

RCC_OscInitStruct.PLL.PLLQ = 8;

HAL_RCC_OscConfig(&RCC_OscInitStruct);

RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;

RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3);

return;

This is my main routine:

void main() {

HAL_SuspendTick();

volatile uint32_t x;

for (int i = 0; i < 599999; i++) {

for (int y = 0; y < 9; y++) {

volatile uint32_t x = +y;

}

__HAL_RCC_PWR_CLK_ENABLE();

__HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);

HAL_PWR_EnableBkUpAccess();

__HAL_RCC_BACKUPRESET_FORCE();

__HAL_RCC_BACKUPRESET_RELEASE();

HAL_PWR_DisableWakeUpPin(PWR_WAKEUP_PIN1);

__HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);

HAL_PWR_EnterSTANDBYMode();

while(1);

}

No wakeup source configure since I just want to test standby current consumption.

Any idea what I am missing?

Thanks in advance.

#low-power-standby

bm · ‎2016-12-21

Posted on December 21, 2016 at 18:22

1. We use a custom PCB but I'll try to find a discovery board. I'll use the same code and see if it behaves the same..

2. Well there is not much to explain. I want to put our device into standby mode to measure the current consumption. Therefore, we disconnected all external ICs, Oscillators, etc.. hooked up a battery and a power monitor. Regarding the code I had a look at the PWR_CurrentConsumption example in the cube package under STM32F411E-Discovery. The measured current consumption is 380ÂµA. Too much for standby mode.

Nesrine M_O · ‎2016-12-21

Posted on December 21, 2016 at 18:30

Hi

Moll.Benjamin

‌,

Try with discovery board to be sure about your software

Then I recommend you to have look to the
http://www.st.com/content/ccc/resource/technical/document/application_note/76/f9/c8/10/8a/33/4b/f0/DM001157pdf/files/DM001157pdf/jcr:content/translations/en.DM001157pdf

-Nesrine-

bm · ‎2016-12-21

Posted on December 21, 2016 at 18:33

I will do this and let you know, thx!

bm · ‎2016-12-22

Posted on December 22, 2016 at 13:47

It worked on the F411 Discovery board but not on my PCB. I guess I need to double check what draws the additional power :\

But thx anyways.

bm · ‎2016-12-22

Posted on December 22, 2016 at 13:48

oh man; it worked on the F411 Discovery board but not on my PCB. I guess I need to double check what draws the additional power in my design :\

Bertrand DENIS · ‎2016-12-23

Posted on December 23, 2016 at 09:29

When the STM32F4 go into stand-by mode all the IOs are set into High impedance state. So I don't know if you measure the total power consumption of your board but you have to take it into account. Example : one IO driving an external input which will float, etc...

Please note that on STM32L4 you can program each state of IO in standby mode.

bm · ‎2016-12-23

Posted on December 23, 2016 at 11:12

I am measuring the 3,3 line directly before the ST controller. We did a complete strip down of the PCB and removed everything; even the external OSC. Most of the I/O lines now are of course not routed. So no I/O can possibly drive another IC.

strange...

Jaroslav BECKA · ‎2016-12-23

Posted on December 23, 2016 at 15:13

Hi binaryguy,

be sure to configure all unused I/Os to either analog mode or output push-pull low.

bm · ‎2016-12-23

Posted on December 23, 2016 at 15:43

So the 330ÂµA could be traced back to a resistor that should not be present at all.

It's working now. Thank you!

But can someone finally confirm if I need to set my I/Os to analog-in before entering standby or not because in the HAL example code it is not done for standby but only for STOP mode.

Bertrand DENIS · ‎2016-12-23

Posted on December 23, 2016 at 21:36

You don't need because as written above all IOs are automatically set in high impedance when you enter in standby mode.