Arduino-esp32: analogRead() triggers unrelated interrupt

[MaxSNi]

I am experiencing a strange bug:

Whenever i use analogRead(), an unrelated interrupt will also trigger, and by changing around a little i could even get 2 interrupts to trigger with every analogRead().

I have not testet every analog pin, but so far this bug happens with A0, A3, A4, A5, A6, A7, but not A10, A11, A12, A13, A14.

I can reproduce the issue with the code below - every 2 seconds it will trigger AnalogRead() and this will trigger one of the button Interrupts. I have have multiple components hooked up as well, but this did not seem to change anything when i tried removing some of them, or having the button GPIOs unconnected.

const int BUTTON_1 = 25;
const int BUTTON_2 = 26;

void setup() 
{
  pinMode(BUTTON_1, INPUT_PULLUP);  
  pinMode(BUTTON_2, INPUT_PULLUP);

  attachInterrupt(BUTTON_1, int1, FALLING);
  attachInterrupt(BUTTON_2, int2, FALLING);

  Serial.begin(115200);
}

void loop() 
{
  delay(2000);  
  float derp = analogRead(A3);  
  Serial.println(derp);
}

void int1() 
{
  Serial.println("1 Interrupt triggered");
}

void int2() 
{
  Serial.println("2 Interrupt triggered");
}

[Raienryu97]

Hey
Tried the code you posted along with just the board, and yes, the interrupts are being triggered.
If you're looking for a workaround
Change the Pull type to PULLDOWN (and of course you should change the button trigger from GND to Vcc since it's pulled down)

I tried with Pulldown and the problem is solved.

  pinMode(BUTTON_1, INPUT_PULLDOWN);
  pinMode(BUTTON_2, INPUT_PULLDOWN);

Also, maybe you already know this , but just in case, it's never good to Serial.println() inside of an ISR. The best idea would be to update a volatile bool inside of ISR and based on the bool, print in void loop()

[KevinVanthuyne]

Had this issue as well, the workaround works 👍 Very weird that this is still happening though