DeepSleepExternalOrTimeWakeup.ino, wakes up immediately without DeepSleep for 10 seconds

[msfujino]

I am trying “DeepSleepExternalOrTimeWakeup.ino” but it wakes up immediately without DeepSleep for 10 seconds.
I think there is a problem with LINE130 ~ LINE134 in "ArduinoLowPower.cpp".

[grobasoz]

It could be because the same pin PC0 is used for the Wakeup as well as the Escape Pin for programming. I used a different Wake Pin (PA5 = D10) and it works fine.

[msfujino]

I tried changing the pin, but it just wakes up when I put my finger near the pin.
It does not appear to be pulled down.

[grobasoz]

I suggest you initialise the pin to either pullup or pulldown. I use PA5 as it can be used to wake from sleep modes using the attachInterrupt function.

  // Running IRQ Pin
  pinMode(WAKE_UP_PIN, INPUT_PULLUP);
  attachInterrupt(WAKE_UP_PIN, myWakeup, FALLING);

  // Set up the wake-up pin
  LowPower.attachInterruptWakeup(WAKE_UP_PIN, nullptr, FALLING);

[msfujino]

This problem does not occur with ExternalWakeup; it occurs when TimedWakeup and ExternalWakeup are used at the same time.
I think there is a problem with LINE130 ~ LINE134 in "ArduinoLowPower.cpp".

[grobasoz]

I'm using the example you mentioned, viz DeepSleepExternalOrTimedWakeup.ino...

[msfujino]

Here is the code being executed and the serial monitor results.　BSP2.3.0 stack "None"
Nothing is connected to PA5.
It wakes up immediately without sleeping for 10 seconds.

`#include "ArduinoLowPower.h"

#define WAKE_UP_PIN PA5

void setup()
{
Serial.begin(115200);
pinMode(LED_BUILTIN, OUTPUT);
digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
Serial.println("Deep sleep with external or timed wakeup");

// Running IRQ Pin
pinMode(WAKE_UP_PIN, INPUT_PULLUP);
attachInterrupt(WAKE_UP_PIN, myWakeup, FALLING);
// Set up the wake-up pin
LowPower.attachInterruptWakeup(WAKE_UP_PIN, nullptr, FALLING);
}

void loop()
{
digitalWrite(LED_BUILTIN, LED_BUILTIN_ACTIVE);
delay(500);
digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
delay(500);

Serial.printf("Going to deep sleep for 10s at %lu\n", millis());
LowPower.deepSleep(10000);
}

void myWakeup () {
}`

`09:44:17.389 -> Going to deep sleep for 10s at 1014

09:44:17.980 -> Deep sleep with external or timed wakeup

09:44:18.995 -> Going to deep sleep for 10s at 1014

09:44:19.589 -> Deep sleep with external or timed wakeup

09:44:20.604 -> Going to deep sleep for 10s at 1014

09:44:21.197 -> Deep sleep with external or timed wakeup

09:44:22.215 -> Going to deep sleep for 10s at 1014

09:44:22.776 -> Deep sleep with external or timed wakeup

09:44:23.791 -> Going to deep sleep for 10s at 1014

09:44:24.380 -> Deep sleep with external or timed wakeup

`

[grobasoz]

I tested your code and it worked fine. At 11:06:54 I triggered a Pin Wake (PA5).

11:06:28.091 [10.657] RX> Deep sleep with external or timed wakeup
11:06:29.071 [00.979] RX> Going to deep sleep for 10s at 1037
11:06:39.735 [10.663] RX> Deep sleep with external or timed wakeup
11:06:40.716 [00.980] RX> Going to deep sleep for 10s at 1037
11:06:51.380 [10.662] RX> Deep sleep with external or timed wakeup
11:06:52.361 [00.979] RX> Going to deep sleep for 10s at 1037
11:06:54.852 [02.490] RX> Deep sleep with external or timed wakeup
11:06:55.833 [00.979] RX> Going to deep sleep for 10s at 1037
11:07:06.497 [10.662] RX> Deep sleep with external or timed wakeup
11:07:07.479 [00.980] RX> Going to deep sleep for 10s at 1037
11:07:18.142 [10.661] RX> Deep sleep with external or timed wakeup
11:07:19.122 [00.978] RX> Going to deep sleep for 10s at 1037

[msfujino]

It's strange. My XIAO_MG24 is floating in the air with nothing connected to its pins except it is connected to the PC via USB-C so that it is not affected by its surroundings.

I am wondering why LINE130-134 in ArduinoLowPower.cpp has a different command order compared to LINE102-108. If I change the order to be similar to LINE102-108, the problem will not occur.

[grobasoz]

OK - I see now. You want to enable Pin Retention on exit from EM4?
Yes, I suppose that would be necessary if the pin was intended to be just left floating...
In my testing, I had the PA5 pin set to a defined state - either High or Low, never just floating.

[msfujino]

A mechanical switch was assumed for the wake-up signal.