NOT able to generate clock pulse

Using Arduino Programming Questions
1 
#include <Arduino.h>
#include <esp32-hal-timer.h>

// Pin definitions
const int buttonPin = 34;    // Pin connected to the button
const int clockPin = 18;    // Pin connected to the clock output

// Timer variables
hw_timer_t * timer = NULL;
portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;
volatile bool clockRunning = false;

// Interrupt service routine for the timer
void IRAM_ATTR onTimer() {
  digitalWrite(clockPin, !digitalRead(clockPin)); // Toggle clock pin state
}

// Interrupt service routine for the button
void IRAM_ATTR buttonISR() {
  // Debouncing delay
  delay(50);
  
  // Check button state again to ensure it's still pressed
  if (digitalRead(buttonPin) == LOW) {
    // Toggle clock running state
    clockRunning = !clockRunning;
    
    if (clockRunning) {
      // Start the timer
      timerAlarmEnable(timer);
      Serial.println("Clock started.");
    } else {
      // Stop the timer
      timerAlarmDisable(timer);
      digitalWrite(clockPin, LOW);   // Set clock pin low
      Serial.println("Clock stopped.");
    }
  }
}

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Configure button pin
  pinMode(buttonPin, INPUT_PULLUP);

  // Configure clock pin
  pinMode(clockPin, OUTPUT);
  digitalWrite(clockPin, LOW);  // Start with clock pin low

  // Create a timer
  timer = timerBegin(0, 80, true); // Timer 0, divider 80 (1MHz), count up
  timerAttachInterrupt(timer, &onTimer, true); // Attach timer interrupt
  timerAlarmWrite(timer, 100, true); // 100 microsecond period (10 MHz frequency)
  
  // Attach interrupt to the button pin
  attachInterrupt(digitalPinToInterrupt(buttonPin), buttonISR, FALLING);
}

void loop() {
  // Nothing to do here because the action is handled by interrupts
}

there was no error in compiling

But i am not able to generate the clock pulse.

2

On what example did you base your code ?
A delay() and Serial.print() in an ISR is unusual.

3

That's 10KHz NOT 10MHz

4

You never enabled the Alarm
// Start an alarm
timerAlarmEnable(timer);

Are you still using version 3.0.2 or have you reverted back to version 2.n.n

1 Like
5

ok, i will note it.

6

I reverted back to version 2.n.n.
Thank you for informing about the version.

7

Did it work?

8

can you please check this code and tell if any mistakes are there in this code, i have modified it.

@jim-p

#include <Arduino.h>
#include <esp32-hal-timer.h>

// Define the LED pin
const int ledPin = 18;  // GPIO 2
const int switchPin = 34;   // GPIO pin where the switch is connected
volatile bool button = false;

// Define the timer
hw_timer_t *timer = NULL;

void IRAM_ATTR switchInterrupt() 
{
  button = !button;
}

void IRAM_ATTR onTimer() 
{    
  // Create a timer with a 1 second period
  timer = timerBegin(0, 8, true);  // Timer 0, divider 8, count up  # default is 10 MHz the mddle value is divider
  timerAlarmWrite(timer, 500000, true);  // 1 second period, autoreload
  digitalWrite(ledPin, HIGH);  // Turn on the LED  
}

void setup() 
{
  pinMode(ledPin, OUTPUT);                  // LED pin as output
  pinMode(switchPin, INPUT_PULLUP);         // Switch pin as input with pull-up resistor
  attachInterrupt(digitalPinToInterrupt(switchPin), switchInterrupt, FALLING);  // Attach interrupt on falling edge (switch press)
  timerAttachInterrupt(timer, &onTimer,true);
}
  

void loop() 
{
  if (button)
  {
    timerAlarmEnable(timer);
  }
  else
  {
    timerAlarmDisable(timer);
  }

}