Low power modes

[Babyla071]

Hi! I've to use low power modes based on the charge of an external battery with stm32L053R8.
I read the voltage of battery through ADC and if this is less of "x" I enter into low power mode.
I readed datasheet and I see five power modes and I want to use low power run and sleep mode. In this library I see other modes (idle mode, sleep mode , deep sleep mode and shutdown mode). They are the same or not? I can use this for my project? Thank you for help :)

[fpistm]

Idle = sleep mode with PWR_MAINREGULATOR_ON
sleep = sleep mode with PWR_LOWPOWERREGULATOR_ON
deepSleep = stop mode with PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI
shutdown = standby mode ( board reset when leaves this mode)

[Babyla071]

The "low-power run mode" supported by the Nucleo board STM32L053R8, which is it exactly?Perhaps this mode can not be achieved through STM32duino.

[fpistm]

With this library the "low-power run mode" is not available, API is based on Arduino one.
Maybe, a new API could be added to support it for compatible MCU.

To get it the clock config should use the MSI clock source.
Then Low Power Run Mode could be call to go in LP RUN and the set Regulator is in LP mode .

This could be done at the sketch level as all HAL APIs are available and the systemCoreClockConfig could be redefined to use the MSI.
Then do a function to enter in lp run mode calling:

    /* Enter LP RUN mode */
    HAL_PWREx_EnableLowPowerRunMode();

    /* Wait until the system enters LP RUN and the Regulator is in LP mode */
    while(__HAL_PWR_GET_FLAG(PWR_FLAG_REGLP) == RESET)
    {
    }

Example are available in the STM32CubeL0 under:
STM32Cube_FW_L0_V1.10.0\Projects\STM32L053R8-Nucleo\Examples\PWR\PWR_LPRUN

[Babyla071]

Hi, I'm trying to use the low power mode. I want that, if the value of ADC is < of 900, the mcu enter in low power mode. If this value is or return > 900, mcu exit of low power. I write this but I don't understand the function attachInterrupt and what is the value repetitionIncrease (I write this code on external wakeup example). Thank you for help.

#include "STM32LowPower.h"

// Blink sequence number
// Declare it volatile since it's incremented inside an interrupt
volatile int repetitions = 1;

// Pin used to trigger a wakeup
const int pin = USER_BTN;

void setup() {
  Serial.begin(9600);

  // pinMode(LED_BUILTIN, OUTPUT);
  // Set pin as INPUT_PULLUP to avoid spurious wakeup
  pinMode(pin, INPUT_PULLUP);

  // Configure low power
  LowPower.begin();
  // Attach a wakeup interrupt on pin, calling repetitionsIncrease when the device is woken up
  LowPower.attachInterruptWakeup(pin, repetitionsIncrease, RISING);
}

void loop() {

  int valore= analogRead(A1);
  Serial.println(valore);
  delay(1000);
  // put your main code here, to run repeatedly:
  
  /*for (int i = 0; i < repetitions; i++) {
    digitalWrite(LED_BUILTIN, HIGH);
    delay(500);
    digitalWrite(LED_BUILTIN, LOW);
    delay(500);
  }*/
  // Triggers an infinite sleep (the device will be woken up only by the registered wakeup sources)
  // The power consumption of the chip will drop consistently
  if(valore<=900)
  LowPower.sleep();
  else digitalWrite(USER_BTN,LOW);
}

void repetitionsIncrease() {
  // This function will be called once on device wakeup
  // You can do some little operations here (like changing variables which will be used in the loop)
  // Remember to avoid calling delay() and long running functions since this functions executes in interrupt context
  repetitions ++;
}

[fpistm]

As a first read, why doing a digitalWrite(USER_BTN,LOW);, it's an input.
The attachInterrupt is to be able to wakeup the board on an external event but only SYS Wakeup pins can be used.
For the L053:
https://github.com/stm32duino/Arduino_Core_STM32/blob/master/variants/NUCLEO_L053R8/PinNamesVar.h

#ifdef PWR_WAKEUP_PIN1
    SYS_WKUP1 = PA_0,
#endif
#ifdef PWR_WAKEUP_PIN2
    SYS_WKUP2 = PC_13,
#endif

So USER_BTN can be used as it is a SYS WKUP pin:
https://github.com/stm32duino/Arduino_Core_STM32/blob/0f1a0ec7eb26fe369a4d5e3354c77d24026ca902/variants/NUCLEO_L053R8/variant.h#L115

// On-board user button
#define USER_BTN PC13

So when you press the user button, the board is woken up and the attached handler increase the number.
This is just to know how many time the board exit from sleep mode.

[Babyla071]

Perfect, I did not remember this SYS wakeup mode for the pins but I don't understand how can I wakes up the board when the value of ADC is highest of "900". Maybe I have to set this SYS wake up pin high with digitalWrite where the condition of the else is true ? (valore>900).
Thank you for the help!

[fpistm]

Sorry, @Babyla071, I thought I've answered you.
About the ADC value, I guess the simplest way is to go in low power then wake up periodically using alarm to check the read the ADC because in LP mode you will not be able to read ADC.
Or if you want use the syswakeup, I guess you need external circuit to handle set to high if you reach your value.

[fpistm]

Closed as no feedback and considered as answered.