Getting Pin Change Interrupts working together with Timer interrupts / sleep(XX ms) on Arduino Pro Mini

[BearWithBeard]

@Joost There has been an attempt to do this a few years ago. I don't know if they ever got it working though: https://forum.mysensors.org/topic/7197/sleep-time-and-external-interrrupts

Besides that, you could request the current time from the controller on interrupts and calculate the remaining sleep duration from there or, as mentioned before, use an external RTC.

[Yveaux]

@Joost I implemented a way to get the remaining sleep time, albeit only roughly on AVR: https://forum.mysensors.org/topic/9595/interrupted-sleep/11

[zboblamont]

@Joost My only thought on the RTC is separation of the timing aspect allowing the processor to go deep-sleep forever until Interrupt. I have one set up to hourly scan my water tank, but I can press a button in parallel with the interrupt to ground for ad-hoc update.

[Joost]

@zboblamont Thanks, will think about that if a pure software approach fails! Though I'd really like to keep complexity down; I'm planning on fabricating at least 10-20 nodes of that kind (by hand).

[Joost]

@Yveaux Thanks, very cool and promising, will take a more in depth look tomorrow!
I just threw that in my code quickly tonight, so far I got a 5 digit number back, but that was always the same also with different wake up delays via PCInt after going to sleep().

[Yveaux]

@Joost as documented it can be roughly 8 seconds off on avr. When an avr is set to sleep for 8 seconds (the maximum watchdog sleep time) and it is woken by an interrupt, it will not know how much time is remaining and always return the same time remaining.
Try sleeping for a minute, then interrupt after 1 second and after half a minute. The remaining time should be different.

[Joost]

@Yveaux said in Getting Pin Change Interrupts working together with Timer interrupts / sleep(XX ms) on Arduino Pro Mini:

@Joost as documented it can be roughly 8 seconds off on avr. When an avr is set to sleep for 8 seconds (the maximum watchdog sleep time) and it is woken by an interrupt, it will not know how much time is remaining and always return the same time remaining.
Try sleeping for a minute, then interrupt after 1 second and after half a minute. The remaining time should be different.

@Yveaux Hi, yeah, I was already expecting the 8s inaccuracy (which is no problem at all, I am planning to cover intervals of several hours).
I tried yesterday night with sleep times of 1-5 minutes and could not get it to work at that point (always receiving identical numbers though the time to awakening the node with PCInt differed), but this might be because I just hacked it in an otherwise more complicated sketch.

I'll start now with making up a minimal test sketch to get the hang of it!
Thanks, J

[Joost]

@Yveaux & others:
So this works great! Here is an example sketch to get Pin Change Interrupts working together with timer-based sleep(). There will be identification of the triggered pin as well as discrimination between rising and falling edge. To test, just add a jumper wire to pin A1 or/and A2 to a Arduino Pro Mini and short it to Ground to wake the Arduino out of a timed sleep() (a connected Radio, here a RFM95, is needed to get the sketch started).

#include <Arduino.h>

#define MY_RADIO_RFM95
#include <MySensors.h>

volatile int isrcounter = 0, timercounter=0;
volatile char PinRegLast, ChangedPin, PinRegister;
volatile boolean isr_interrupted;
uint32_t remainingSleepTime = 0;

ISR(PCINT1_vect)
{
    PinRegister = PINC;
    ChangedPin = PinRegister ^ PinRegLast;
    PinRegLast = PinRegister;
    _wokeUpByInterrupt = 0xFE;
    isr_interrupted=true;
    isrcounter++;
}

void setup()
{
noInterrupts();
PCICR |= 0b00000011; // Enables Ports B and C Pin Change Interrupts
PCMSK1 |= 0b00000110; //PCINT9 & PCINT10 = A1 & A2
PCIFR  = B00000001; // Reset Interruptflag
pinMode(A1, INPUT_PULLUP); pinMode(A2, INPUT_PULLUP);
PinRegister = PINC;
interrupts();
Serial.begin(38400);
}

void presentation() {}

void loop()
{
  noInterrupts();
  if ( isr_interrupted ) {
    isr_interrupted = false;
    switch (ChangedPin){
    case (1 << PINC1):
      if (~PinRegister & (1 << PINC1)) { 
        Serial.print("Interrupted / Woken up by Pin A1, remaining sleep() time: ");  
        remainingSleepTime = getSleepRemaining();
        Serial.println( remainingSleepTime );}
      else { 
        Serial.println("Falling edge of Pin A1"); 
       } 
      break;
    case (1 << PINC2):
      if (~PinRegister & (1 << PINC2)) { 
        Serial.print("Interrupted / Woken up by Pin A2, remaining sleep() time: "); 
        remainingSleepTime = getSleepRemaining();
        Serial.println( remainingSleepTime );}
      else { 
        Serial.println("Falling edge of Pin A2"); 
       }
      break;
    default:
      break;
    interrupts();
    }
  }
  else  { 
    interrupts();
    Serial.println("Timer wake up / Loop"); 
    timercounter++; 
    }

  Serial.print("  ");  Serial.print(" ISR Counter: ");Serial.print(isrcounter);  Serial.print("   Timer counter: "); Serial.println(timercounter);
  sleep((uint32_t) 60*1000);
}

Thanks a lot! Joost

[evb]

@Joost I like your solution to be able to use other pins as pin change interrupts together with Timer interrupts in the MySensors library.

I did use the default sleep function of MySensors with the foreseen D1 and D2 pins where D1 is already taken by the radio, so only D2 is usable for custom use.
See https://www.mysensors.org/download/sensor_api_20#sleeping

[r-nox]

I think this is the same thing as you were trying to accomplish.

Sleep for 6 minutes or when interrupted. I have a reed switch on pin 2

pinMode(REED_SWITCH, INPUT);   // set the reed switch digital pin as input
//digitalWrite(REED_SWITCH, HIGH);
pinMode(REED_SWITCH, INPUT_PULLUP);

sleep(digitalPinToInterrupt(REED_SWITCH), CHANGE, 360000); //3600000 hour