CODEWITHSUNDEEP
avrinterrupt-handlingmicrochipatmelattiny
Felix Mark
Felix Mark

Reputation: 11

ATTiny 1626 pullup input does not trigger falling edge ISR, is there something wrong with my setup?

I have an ATTiny 1626 on a PCB which I program by using SerialUPDI. I want to increase the value of a variable in an interrupt service routine, triggered by a button press. The problem is, that the ISR does not get called at all.

My Setup

My Code is:

// Global:
volatile short operation_mode = 1;      // Track operation mode

void setup() {
    cli();
    PORTA.PIN2CTRL |= PORT_PULLUPEN_bm;     // Enable pin A2 pull-up resistor
    PORTA.PIN2CTRL |= PORT_ISC_FALLING_gc;  // Enable pin A2 falling edge interrupts
    PORTA.DIRSET &= ~PIN2_bm;               // Set pin A2 as INPUT  -> Internal pull-up required for async button interrupt
    sei();
}

void loop() {
    ADC0_CTRLA |= ADC_ENABLE_bm; // Turn on ADC
    delay(10);
    // [...]
    ADC0_CTRLA &= ~ADC_ENABLE_bm;       // Turn off ADC
    set_sleep_mode(SLEEP_MODE_STANDBY); // Set standby sleep mode
    sleep_enable();                     // Enable sleeping
    sleep_cpu();                        // Sleep until woken up by ISR
}

// The ISR:
ISR(PORTA_PORT_vect) {
  if ((PORTA.INTFLAGS & PIN2_bm) == 0) {
    operation_mode = (operation_mode + 1) % 3;
  }
  PORTA.INTFLAGS |= PIN2_bm;  // Clear interrupt flag
}

I wonder if there is something wrong with my code or if my setup is flawed. Maybe a capacitor, which has too much capacitance causes the falling edge to be less steep and makes the uC not detect it? I am a bit out of ideas, help is highly appreciated!

Upvotes: 1

Views: 277

Answers (0)

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