Stepper motor pausing while printing the speed of the motor on Display 20x4

[i_am_pku]

Using NEMA 23 stepper motor with R60 and 20x4 LCD but while changing the speed of motor and display the same. I tried with Timer interrupt one for LCD display and one for Motor running code but not able to fix it. Below I am pasting my code. Can somebody provide their guidance to fix this issue?

#include <AccelStepper.h>
#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

#define stepPin 10
#define dirPin 11

// Define the pins for the switches
const int increaseSpeedPin = 15;
const int decreaseSpeedPin = 16;

// Define the stepper motor and the pins it will use
AccelStepper stepper(AccelStepper::DRIVER, stepPin, dirPin); // Pin 2 for STEP, Pin 3 for DIRECTION

// Variables to store the current speed
int speed = 800;
int last_speed = 0;
const int maxSpeed = 6000; // Adjust this value as needed

unsigned long currentMillis = 0;
unsigned long lastDebounceTimeSpeedUp = 0;
unsigned long lastDebounceTimeSpeedDown = 0;
const unsigned long debounceDelay = 150; // Debounce delay in milliseconds
const unsigned long displayDelay = 150; // Debounce delay in milliseconds

void setup() {

  // Set up the LCD's number of columns and rows:
  lcd.begin(20, 4);

  lcd.print("Motor Speed: ");
  lcd.print(speed);

  // Set up the pins for the switches
  pinMode(increaseSpeedPin, INPUT_PULLUP);
  pinMode(decreaseSpeedPin, INPUT_PULLUP);

  // Set the maximum speed and acceleration
  stepper.setMaxSpeed(maxSpeed);
  stepper.setAcceleration(500); // Adjust this value as needed

  noInterrupts();           // Disable all interrupts
  // Enable pin change interrupt for PCINT12 (PC4), PCINT10 (PC2), and PCINT9 (PC1)
  PCICR |= (1 << PCIE1);  // Enable pin change interrupt for PCINT[14:8]
  PCMSK1 |= (1 << PCINT12) | (1 << PCINT10) | (1 << PCINT9); // Enable interrupts for PCINT12, PCINT10, and PCINT9
  interrupts();             // Enable all interrupts
  
  stepper.setSpeed(speed);
}

void loop() {
  // Run the stepper motor at the set speed
  stepper.runSpeed();
  
  // Check if the increase speed button is pressed
  if(speed != last_speed) {
    lcd_disp();
  }
}

void lcd_disp() {
  currentMillis = millis(); // Get the current time
  if (digitalRead(increaseSpeedPin) == LOW && (currentMillis - lastDebounceTimeSpeedUp) > displayDelay) {
    lastDebounceTimeSpeedUp = currentMillis;
    lcd.setCursor(13, 0);
    lcd.print("    "); // Clear previous value
    lcd.setCursor(13, 0);
    lcd.print(speed);
    last_speed = speed;
  }
}

ISR(PCINT1_vect) {
  currentMillis = millis(); // Get the current time
  if (digitalRead(increaseSpeedPin) == LOW && (currentMillis - lastDebounceTimeSpeedUp) > debounceDelay) {
    lastDebounceTimeSpeedUp = currentMillis;
    speed += 25;    
    stepper.setSpeed(speed);
  } else if(digitalRead(decreaseSpeedPin) == LOW && (currentMillis - lastDebounceTimeSpeedDown) > debounceDelay) {
    lastDebounceTimeSpeedDown = currentMillis;
    speed -= 25;    
    stepper.setSpeed(speed);
  }
}

[Paul_KD7HB]

All LCD displays have to be blocking because you must wait until the LCD processor is finished with the current command. Try displaying the current speed only once per second.

[Railroader]

I would read the buttons inside loop. It runs more than fast enough for that.

As @ Paul_KD7HB says, update the display some 3 times, max 5 times, per second. No eye catches 100 or 1000 updates per second.

[i_am_pku]

But I need to display live. So no choice.

[i_am_pku]

I tried this, result was, Motor getting pause for more time so facing big jerk.

[i_am_pku]

My issue got resolved. Used PWM with 50% duty cycle to run motor and update the speed (Increase/Decrease) into the PCINTx ISR for 2 push button and LCD code is inside the loop () function but LCD changes will display if speed updated.

[Railroader]

@i_am_pku

So no choice.

Oh yes. Use millis and update display if more than decired hundred milliseconds have elapased since last time! Update lastTimeUpdate-variable!