How to reset Arduino UNO

How to reset Arduino UNO


Struggling with resetting your Arduino UNO? Our comprehensive blog is here to help! Start with an introduction to the Arduino UNO and the importance of the reset function. Learn about the reset pin and explore various methods to reset your board, from manual to software-based techniques. Troubleshooting tips are also provided to help you overcome common issues. This guide is perfect for beginners and experienced users alike, ensuring smooth and efficient project development. Click now to master the art of resetting your Arduino UNO!


The Arduino UNO is a popular and versatile open-source microcontroller which is favored by many from beginners to experts.  Resetting the board can help you restart your program, recover from a non-responsive state, or clear memory for a fresh start.

Understanding how to reset your Arduino UNO effectively is crucial for troubleshooting and ensuring smooth operation of your projects. In this blog you will walk through the various methods to reset your Arduino UNO.

Whether you're a beginner or an experienced user, knowing these techniques will enhance your ability to manage and maintain your Arduino UNO efficiently.

What is reset pin?

The reset pin in Arduino will help in restarting the microcontroller. When this pin is brought LOW, it triggers a reset, effectively restarting the entire board. The reset function will let you restart the current running program and trigger the bootloader for uploading a new sketch.

Methods to reset Arduino UNO

Resetting your Arduino Uno can help in troubleshooting, restarting your code, or ensuring a fresh start for your project. There are several methods used to reset your Arduino Uno:

Reset button

The simplest way to reset a Arduino Uno is using the physical reset button. It is usually in the bottom left corner of the board, press and hold it for a few seconds before releasing. This will ensure a proper reset of your board

Using Reset Pin

The reset pin, which is labelled as “reset” is connected to the reset circuit of the microcontroller, When this pin is pulled low i.e.. 0V, it will trigger the rest function of the microcontroller. Configure the Digital output pin as digital output pin by using pinMode() function, and program it to LOW.

const int OUTPUT_PIN = 2;

void setup()


digitalWrite(OUTPUT_PIN, HIGH);



Serial.println("How to Reset Arduino Programmatically");


void loop()


Serial.println("Arduino will be reset after 5 seconds");


digitalWrite(OUTPUT_PIN, LOW);

Serial.println("Arduino never run to this line");


Using software reset

A software reset is done using the code only, which will give the user the ability to completely automate.


void setup() {

  // Initialize Serial for debugging


  Serial.println("System will reset in 15 milliseconds...");


  // Enable the watchdog timer with a 15ms timeout



  // Enter an infinite loop, waiting for the watchdog to reset the microcontroller

  while (true) {

    // Do nothing, just wait for the reset




void loop() {


Disabling Auto-Reset on Serial Connection

This is done on a program that is expected to continuously run and communicate over serial port , and thus you don’t want a reset each time a connection is made.

To disable the automatic reset of the Arduino board upon serial connection, just stick a 120 Ohm resistor between the RESET and +5V pins, It is as simple as that. The resistor will keep the RESET pin pulled high, preventing the auto-reset when the serial connection is opened.

Trouble shoots

  • Arduino UNO is not getting reset even after pressing the Reset button Try to press the Reset button firmly and hold for few seconds, if the Arduino still does not reset, check for physical damages of the reset button, a poor solder joint or loose connection on the reset button can prevent it from working.
  • If the Arduino Uno is not getting reset over Serial communication. If the serial monitor software does not handle the DTR signal correctly, the auto-reset may not trigger therefore ensure your serial monitor settings are correct and some terminal programs will allow you to configure the DTR manually.
  • If the Arduino is stuck in the Reset loop. There is a probability that a faulty sketch can cause the Arduino to continuously reset. Incorrect use of watchdog timer can also cause your Arduino to continuously reset, so crosscheck the watchdog timer settings or disable the same.
  • Bootloader problem. A corrupt bootloader can prevent the Arduino to reset and turning on correctly, re-run the bootloader to see if it fixes the issue.


Even when the Arduino is the most favored microcontroller for vast group of people from the beginners to the experts, knowing how to reset your Arduino Uno is essential for restarting your program, recovering from a non-responsive state, or clearing memory for a fresh start.

This learning will help you in re-starting, troubleshooting therefore allowing a smooth flow of your project. In this blog, we have explored various methods to reset your Arduino Uno, including using the reset button, the reset pin, and software resets. We've also covered disabling auto-reset on serial connections and provided troubleshooting tips for common reset issues.

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Frequently Asked Questions

1. Why do I need to reset my Arduino Uno?

Resetting your Arduino Uno is necessary to restart your program, recover from a non-responsive state, or clear memory for a fresh start. It can also be useful for reinitializing the board when uploading new sketches or making significant changes to your code.

2. How do I reset my Arduino Uno using the reset button?

To reset your Arduino Uno using the reset button, simply press and hold the button located near the USB port or in the bottom left corner of the board for a few seconds, then release it. This will restart the microcontroller and reload your current sketch.

3. How can I disable the auto-reset feature on my Arduino Uno when using serial communication? 

To disable the auto-reset feature on your Arduino Uno during serial communication, place a 120 ohm resistor between the RESET and 5V pins. This will keep the RESET pin pulled high and prevent the board from resetting when the serial connection is opened.

4. What should I do if my Arduino Uno doesn’t reset when I press the reset button?

If your Arduino Uno doesn’t reset when you press the reset button, try pressing the button firmly and holding it for a few seconds. If it still doesn’t work, check for physical damage to the button, poor solder joints, or loose connections. You can also try resetting the board using the reset pin with a jumper wire.

5. How can I troubleshoot if my Arduino Uno is stuck in a reset loop?

If your Arduino Uno is stuck in a reset loop, it could be due to a faulty sketch or incorrect use of the watchdog timer. Try uploading a simple sketch like the Blink example to see if the problem persists. If the simple sketch works, there may be an issue in your original code that needs debugging. Also, ensure the watchdog timer settings in your code are correct or disable the watchdog timer if necessary. If the problem persists, consider re-burning the bootloader using another Arduino as an ISP.

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