Unable to use RTC Alarm and Wakeup pin as Wakeup source Simultaneously

[Talal-Zahid786]

Hi! I was working on a project where I need RTC Alarm wakeup and Wakeup pin simultaneously to wake up the STM32F103C8T6 BluePill Development board from SHUTDOWN Mode. Both Wakeup Sources work if I use them alone. But when I use them Together RTC Alarm never works. Only WakeUp Interrupt Works.

Here is my testing Code:

#include <STM32LowPower.h>
#include <STM32RTC.h>

STM32RTC& rtc = STM32RTC::getInstance();

volatile bool rtcWakeFlag = false;
volatile bool IntrptWakeFlag = false;

uint8_t hours = 23;
uint8_t minutes = 59;
uint8_t seconds = 30;
uint32_t subSeconds = 0;

uint8_t weekDay = 5;
uint8_t day = 22;
uint8_t month = 8;
uint8_t year = 25;

void rtcWakeup(void *data) {
  rtcWakeFlag = true;
}

void pinWakeup(){
  IntrptWakeFlag = true;
  // Serial.println("Woke up from sleep via Interrupt!");
}

void setup() {
  // Serial.begin(115200);
  pinMode(PC13,OUTPUT);
  pinMode(PA0,INPUT_PULLUP);
  // digitalWrite(PC13,HIGH);
  LowPower.begin();
  LowPower.attachInterruptWakeup(PA0, pinWakeup, RISING, SHUTDOWN_MODE);
  LowPower.enableWakeupFrom(&rtc, rtcWakeup);
  digitalWrite(PC13,HIGH);
  rtc.setClockSource(STM32RTC::LSE_CLOCK);
  rtc.configForLowPower(STM32RTC::LSE_CLOCK);
  rtc.begin();
  rtc.setTime(hours, minutes, seconds, subSeconds);
  rtc.setDate(weekDay, day, month, year);
  // // Set RTC Alarm for 30 seconds later
  rtc.getTime(&hours, &minutes, &seconds, &subSeconds);
  rtc.getDate(&weekDay, &day, &month, &year);
  rtc.attachInterrupt(rtcWakeup,rtc.ALARM_A);
  rtc.setAlarmTime(0, 0, 0, rtc.ALARM_A);
  rtc.setAlarmDay(day+1);
  rtc.enableAlarm(rtc.MATCH_DHHMMSS,rtc.ALARM_A);
  digitalWrite(PC13,LOW);
  delay(500);
  digitalWrite(PC13,HIGH);
  delay(500);
  delay(5000);
  // HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN1);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(rtcWakeFlag){
    rtcWakeFlag = false;
    rtc.setTime(23, 59, 30, 0);
    rtc.setDate(1, 1, 1, 1);
    rtc.getTime(&hours, &minutes, &seconds, &subSeconds);
    rtc.getDate(&weekDay, &day, &month, &year);
    for (int i = 0; i<3; i++){
      digitalWrite(PC13,LOW);
      delay(500);
      digitalWrite(PC13,HIGH);
      delay(500);
    }
    rtc.setAlarmTime(0, 0, 0, rtc.ALARM_A);
    rtc.setAlarmDay(day+1);
    rtc.enableAlarm(rtc.MATCH_DHHMMSS,rtc.ALARM_A);
  }
  if(IntrptWakeFlag){
    IntrptWakeFlag = false;
    digitalWrite(PC13,LOW);
    delay(500);
    digitalWrite(PC13,HIGH);
    delay(500);
  }
  LowPower.shutdown();
}

[fpistm]

Hi @Talal-Zahid786
it seems you met the issue related in the errata sheet:

[mgergos]

Hi Fred,

This is may be related, so I'll post it here;

I'm trying to use LowPower.shutdown(3000); whilst a wakeup pin is configured as a wake source.

I tried the following code on the NUCLEO-WL55JCx.
B1_BTN - Remain in shutdown whilst held.
B2_BTN - Shutdown for 3 seconds if pressed.

One would expect the Reset (of the B2_BTN 3-Sec Shutdown) to reinitialise the B1_BTN interrupt, but seems not to be the case.

B1_BTN interrupt works fine, up until B2_BTN interrupt is used once, then the B1_BTN interrupt no longer works correctly.
i.e. wakes immediately and requires a power-down reset to restore B1_BTN functionality.

I trust you can help me understand - Any fix or workaround would be greatly appreciated.

Cheers,
M.

#include <STM32LowPower.h>  // Low Power@^1.5.0
#include <STM32RTC.h>       // RTC@^1.8.0

STM32RTC& rtc = STM32RTC::getInstance();

void callbackFunction(){}

void setup(void){
  pinMode(LED_RED, OUTPUT);
  pinMode(LED_BLUE, OUTPUT);   
  pinMode(B1_BTN, INPUT_PULLUP);
  pinMode(B2_BTN, INPUT_PULLUP);
  // Sustain B1_BTN pullup in shutdown mode
  HAL_PWREx_EnablePullUpPullDownConfig();
  HAL_PWREx_EnableGPIOPullUp(PWR_GPIO_A, GPIO_PIN_0);

  rtc.setClockSource(STM32RTC::LSE_CLOCK);
  rtc.begin();

  LowPower.begin();
  LowPower.attachInterruptWakeup(B1_BTN, callbackFunction, RISING, SHUTDOWN_MODE);  // Wake upon B1_BTN release

  // Hello world
  digitalWrite(LED_RED, HIGH); delay(1000); digitalWrite(LED_RED, LOW);
}

void loop() {
  // Verify RTC running
  digitalWrite(LED_BLUE, bitRead(rtc.getEpoch(), 0));

  // Shutdown whilst B1_BTN held
  if(!digitalRead(B1_BTN)){LowPower.shutdown();}

  // if B2_BTN pressed, shutdown for 3 secs
  if(!digitalRead(B2_BTN)){LowPower.shutdown(3000);}
}

[mgergos]

Hi Fred,

This is may be related, so I'll post it here;

I'm trying to use LowPower.shutdown(3000); whilst a wakeup pin is configured as a wake source.

I tried the following code on the NUCLEO-WL55JCx. B1_BTN - Remain in shutdown whilst held. B2_BTN - Shutdown for 3 seconds if pressed.

One would expect the Reset (of the B2_BTN 3-Sec Shutdown) to reinitialise the B1_BTN interrupt, but seems not to be the case.

B1_BTN interrupt works fine, up until B2_BTN interrupt is used once, then the B1_BTN interrupt no longer works correctly. i.e. wakes immediately and requires a power-down reset to restore B1_BTN functionality.

I trust you can help me understand - Any fix or workaround would be greatly appreciated.

Cheers, M.

#include <STM32LowPower.h>  // Low Power@^1.5.0
#include <STM32RTC.h>       // RTC@^1.8.0

STM32RTC& rtc = STM32RTC::getInstance();

void callbackFunction(){}

void setup(void){
  pinMode(LED_RED, OUTPUT);
  pinMode(LED_BLUE, OUTPUT);   
  pinMode(B1_BTN, INPUT_PULLUP);
  pinMode(B2_BTN, INPUT_PULLUP);
  // Sustain B1_BTN pullup in shutdown mode
  HAL_PWREx_EnablePullUpPullDownConfig();
  HAL_PWREx_EnableGPIOPullUp(PWR_GPIO_A, GPIO_PIN_0);

  rtc.setClockSource(STM32RTC::LSE_CLOCK);
  rtc.begin();

  LowPower.begin();
  LowPower.attachInterruptWakeup(B1_BTN, callbackFunction, RISING, SHUTDOWN_MODE);  // Wake upon B1_BTN release

  // Hello world
  digitalWrite(LED_RED, HIGH); delay(1000); digitalWrite(LED_RED, LOW);
}

void loop() {
  // Verify RTC running
  digitalWrite(LED_BLUE, bitRead(rtc.getEpoch(), 0));

  // Shutdown whilst B1_BTN held
  if(!digitalRead(B1_BTN)){LowPower.shutdown();}

  // if B2_BTN pressed, shutdown for 3 secs
  if(!digitalRead(B2_BTN)){LowPower.shutdown(3000);}
}

Seems that STM32Duino doesn't clear the RTC flags.
Status Register RTC_SR bits need to be cleared manually as they live in the Backup domain.
For the above example, the workaround is adding this line to setup()

__HAL_RTC_ALARM_CLEAR_FLAG(&rtc, RTC_FLAG_ALRAF);

[fpistm]

Hi @mgergos
Thanks for input, will try to check soon.
Do not hesitate to provide a PR