ATTiny85 Interrupts in Arduino IDE - c++

Question

I have an ATTiny85 which I program using a sparkfun programmer (https://www.sparkfun.com/products/11801) and the ATTiny Board Manager I am using is: https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json
Below is my code, I am having trouble getting the interrupt to work when I ground Pin 2.
I have tested the LED does work outside of the interrupt (inside the loop). Any suggestions are welcome.
#include "Arduino.h"
#define interruptPin 2
const int led = 3;
bool lastState = 0;
void setup() {
pinMode(interruptPin, INPUT_PULLUP);
attachInterrupt(interruptPin, pulseIsr, CHANGE);
pinMode(led, OUTPUT);
}
void loop() {
}
void pulseIsr() {
if (!lastState) {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
lastState = 1;
}
else {
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
lastState = 0;
}
}

Answer 1

I was way off.
Here is how to set up an interrupt on the ATTiny85 using the Arduino IDE (this example uses digital pin 4 (pin 3 on the chip):
#include "Arduino.h"
const byte interruptPin = 4;
const byte led = 3;
bool lastState = false;
ISR (PCINT0_vect) // this is the Interrupt Service Routine
{
if (!lastState) {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
lastState = true;
}
else {
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
lastState = false;
}
}
void setup() {
pinMode(interruptPin, INPUT_PULLUP); // set to input with an internal pullup resistor (HIGH when switch is open)
pinMode(led, OUTPUT);
// interrupts
PCMSK |= bit (PCINT4); // want pin D4 / pin 3
GIFR |= bit (PCIF); // clear any outstanding interrupts
GIMSK |= bit (PCIE); // enable pin change interrupts
}
void loop() {
}

Answer 2

I see one possible error with your Boolean data type. Boolean data types are either true or false. I see that your using it for variable lastState. The initialization to equal 0 is something that I don't think the compiler allows. Maybe you should try setting the bool variable to the following...
bool lastState = true;
if (!lastState) {
// what you want your code to perform if lastState is FALSE
}
else {
//what else you want your code to perform if lastState is TRUE
}
OR
bool lastState = true;
if (lastState) {
// what you want your code to perform if lastState is TRUE
}
else {
//what else you want your code to perform if lastState is FALSE
}
Here is a helpful pdf on Boolean data types, available for download through my Nextcloud instance.
https://nextcloud.point2this.com/index.php/s/so3C7CzzoX3nkzQ
I know this doesn't fully fix your problem, but hopefully this will help some.