I’m using the STM32 NUCLEO-F401RE microcontroller and have programmed a speaker to change frequency when the joystick is pushed up or down. However, I’m encountering two issues:

1. The frequency sometimes changes multiple times when the joystick is pressed, suggesting the ISR is being triggered more than once.
2. Although the `InterruptIn` object is set to trigger on the rising edge, it sometimes also triggers on the falling edge when the joystick returns to neutral.

I haven’t implemented debouncing yet, and I’m using a digital joystick connected to pins A2 and A3 without external pull-up/down resistors. Here’s the code:

void upISR()
{
    if (greenLED.getStatus())
    {
        myTicker.detach();
        frequency += 200;
        myTicker.attach(callback(&spkr, &Speaker::toggle), 0.5/frequency); 
    }
}

int main()
{
    InterruptIn up(A2);
    InterruptIn down(A3);
    InterruptIn fire(D4);

    up.rise(&upISR);
    down.rise(&downISR);
    fire.rise(&toggleISR);

    redLED.on();

    while (1) {}
}

Could these issues be due to the lack of debouncing? What’s the best way to handle this, and should I be using external pull-up/down resistors to improve reliability?

Any advice would be most appreciated guys 🙏🏽