Moving UNO code with interrupt to ATTINY85

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1

Hi

I have the following code that works on a UNO but i need to make it work on a ATTINY85

I know that the attach interrupt does not work on the ATTINY85.

What is the best way to change the interrupt to work

#include <SwitecX12.h>

const int STEPS = 265*12;
const int A_STEP = 8;
const int A_DIR = 9:
const int RESET = 10;

// Define the potentiometer pin
#define POT_PIN A0

// Define the RPM sensor pin
#define RPM_PIN 2


// Create a SwitecX25 object
SwitecX12 motor1(STEPS, A_STEP, A_DIR);  // steps for 265-degree movement

volatile int rpmCount = 0;
unsigned long lastTime = 0;
unsigned long currentTime = 0;
int rpm = 0.0;

void setup() {

  // Initialize motor
  digitalWrite(RESET, HIGH);  
  motor1.zero();
  motor1.setPosition(0);  // Move needle to zero position



  // Setup RPM sensor interrupt
  pinMode(RPM_PIN, INPUT);
  attachInterrupt(digitalPinToInterrupt(RPM_PIN), rpmISR, RISING);
}


void loop() {
  currentTime = millis();
  // Calculate RPM
  if (currentTime - lastTime >= 1000) {  // Calculate every 1 second


    noInterrupts();
    rpm = (int)(rpmCount * (60.0 / 0.66644) / 6);  // Convert to RPM
    rpmCount = 0;
    interrupts();
    lastTime = currentTime;


    // Read potentiometer value for fine adjustment
    int potValue = analogRead(POT_PIN);
    int fineAdjustment = map(potValue, 0, 1023, -500, 500);      // Adjust between -500 and 500 RPM
    int adjustedRPM = constrain(rpm + fineAdjustment, 0, 5000);  // Constrain to 0-5000 RPM



    // Map RPM to motor position (0 to 260 degrees)
    int motorPosition = map(adjustedRPM, 0, 5000, 0, STEPS);  // Adjust the steps according to your motor's range
    motor1.setPosition(motorPosition + 16);
  }

  // Update motor movement
  motor1.update();
}

// RPM sensor interrupt service routine
void rpmISR() {
  rpmCount++;
}

On the ATTINY85 I have the pins set as

const int A_STEP = 4;
const int A_DIR = 1:
const int RESET = 0;

// Define the potentiometer pin
#define POT_PIN A3

// Define the RPM sensor pin
#define RPM_PIN 2

2

I think interrupts work on the ATtiny85. Check any pinout for PCINTx. Here is a simulation that might help...

  • some libraries will not work with ATtiny85.
3

Thank you

Can I use INT0 instead of PCINT0 or can PCINT0 be used with rising edge

4

INT0 on the ATtiny85 works just like INT0 on the Uno. Pin change interrupts are just that, they react to either change in the pin status.

5

Will this work before I test it on my tiny

#include <AccelStepper.h>
#include <avr/interrupt.h>
#include <avr/io.h>

// defines pins numbers for X12
const int stepPin = 4;
const int directionPin = 1;
const int enablePin = 0;

// Define the potentiometer pin
const int POT_PIN = A3;

// Define the RPM sensor pin
const int RPM_PIN = PINB2; // PB2 INT0

const int STEPS = 265 * 12;

// Define a stepper and the pins it will use
// 1 or AccelStepper::DRIVER means a stepper driver (with Step and Direction pins)
AccelStepper motor(AccelStepper::DRIVER, stepPin, directionPin);

volatile int rpmCount = 0;
unsigned long lastTime = 0;
unsigned long currentTime = 0;
int rpm =0.0;

void setup() {

  cli(); // CLEAR interrupts enabled while configuring interrupts
  GIMSK |= (1 << RPM_PIN); // Enables external interrupt
  MCUCR |= B00000011; // RISING mode
  sei(); // SET interrupts enabled after confiuration is complete

  pinMode(RPM_PIN, INPUT);
 

  motor.setMaxSpeed(1000);
  motor.setSpeed(500);
  digitalWrite(enablePin, HIGH);
  motor.moveTo(0);
}

void loop() {

  currentTime = millis();

  if (currentTime - lastTime >= 1000) {

    cli();

    rpm = (int)(rpmCount * (60.0 / 0.66644)/6);
    rpmCount = 0;

    sei();
    
    lastTime = currentTime;

    int potValue = analogRead(POT_PIN);
    int fineAdjustment = map(potValue, 0, 1023, -500, 500);
    int adjustedRPM = constrain(rpm + fineAdjustment, 0, 5000);

    int motorPosition = map(adjustedRPM, 0, 5000, 0, STEPS);

    motor.moveTo(motorPosition + 16);
    
  }

}

ISR(INT0_vect) {
  cli();
  rpmCount++;
  sei();
}
6

Test it in the simulator.

7

will the simulator have my driver chip on it

8

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