Timer Interrupt using ISR

Official Hardware Nano Family Nano 33 IoT
1

My interrupt code will not compile without errors:

/*
  Interrupt Test Program
    - 2/24/2025
  Author: Terry Benson
*/
// Arduino NANO 33 IoT board selected
#include "SAMDTimerInterrupt.h" // This has no affect on the errors

bool ledOn = false;
const unsigned long TIME_TICKS = 7500; // for 10 ms interrupts at 48 MHz
const bool PRESCALER = B00000011; // Prescaler of 64
const bool ENABLE_ISR = B00000010; // Enable the ISR to generate an interrupt

// ISR for the switch debounce functions using timer 1
ISR (TIMER1_COMPA_vect)
{
    ledOn = !ledOn;   // toggle led
    if (ledOn) {
      digitalWrite(LED_BUILTIN, HIGH);
    } else {
      digitalWrite(LED_BUILTIN, LOW);      
    }
} // End of ISR 

void setup()
{
//  flash the LED at the interrupt rate
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LOW);
  ledOn = false;

// Set up timer for 10 ms interrupts
  TCCR1A = 0;           // Init Timer1A
  TCCR1B = 0;           // Init Timer1B
  TCCR1B |= PRESCALER;  // Set Prescaler
  OCR1A = TIME_TICKS;   // Timer Compare1A Register
  TIMSK1 |= ENABLE_ISR; // Enable Timer COMPA Interrupt
}

void loop()
{
  // set up main function here
}

I get these errors among others (with or without the Included library):
TimerISR_Test\TimerISR_Test.ino:16:5: error: expected constructor, destructor, or type conversion before '(' token
ISR (TIMER1_COMPA_vect)
^
TimerISR_Test\TimerISR_Test.ino:34:3: error: 'TCCR1A' was not declared in this scope
TCCR1A = 0; // Init Timer1A
^~~~~~
Do I need to use different names for the Timer Registers?

2

That code will work only on the Arduino Uno R3 or related AVR processors.

3

Yes, and the interrupts have more than likely different names.

Topic moved to the dedicated Nano33 IoT section of the forum. Do not post in "Uncategorized"; see the sticky topics in Uncategorized - Arduino Forum.

4

Thanks for the response. I'll change to the NANO board.