![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-FreeRTOS-Software-Timers.jpg?resize=1200%2C675&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nNew to FreeRTOS?<\/strong> Here are other FreeRTOS tutorials with the ESP32 that we recommend following:<\/p>\n\n\n\n Using timer interrupts is especially useful to make something happen periodically or after a predefined period without constantly checking the elapsed time.<\/p>\n\n\n A software timer lets you schedule a function to run at a specific time later on. The function that the timer calls is known as its callback function<\/em>, and the interval from when the timer starts until the callback executes is the timer’s period<\/em>.<\/p>\n\n\n\n In FreeRTOS with the ESP32, we have two types of timers available:<\/p>\n\n\n\n Here are some basic concepts about creating and handling FreeRTOS timers with the ESP32 on Arduino IDE:<\/p>\n\n\n\n To create a timer, you use the xTimerCreate<\/strong>()<\/span> function and pass the following parameters as arguments in this order:<\/p>\n\n\n\n For example:<\/p>\n\n\n\n To start a timer use xTimerStart<\/strong>(timer, blockTime)<\/span>. The first argument is the timer handler, and the second argument is the number of seconds to wait before starting the timer.<\/p>\n\n\n\n To stop a running timer, you just need to call xTimerStop<\/strong>(timer, blockTime)<\/span>. The arguments are the same as the previous function.<\/p>\n\n\n\n To reset a timer, which means restarting a timer’s countdown, even if it is already running, call xTimerReset<\/strong>(timer, blockTime)<\/span>. The arguments are the same as the previous functions.<\/p>\n\n\n\n If you want to start a timer from an ISR (interrupt service routine function), you should call xTimerStartFromISR<\/strong>(timer, &higherPriorityTaskWoken)<\/span>.<\/p>\n\n\n\n higherPriorityTaskWoken<\/span> can be pdTRUE<\/span> or pdFALSE<\/span>. Set to pdTRUE<\/span> if the task is of higher priority and we should switch to it immediately. In this case, we should call portYIELD_FROM_ISR()<\/span> from the ISR to switch to that task immediately for real-time responsiveness.<\/p>\n\n\n\n Now that we’ve learned the basics of software timers, we’ll start by testing some simple examples to show you how to create and handle periodic timers (auto-reload) with the ESP32 using FreeRTOS in Arduino IDE.<\/p>\n\n\n The first example we’ll take a look at is a simple Blink LED sketch. This sketch creates a FreeRTOS periodic timer to toggle the state of an LED every second.<\/p>\n\n\n\n This is a simple and easy example to show you how to actually use the timers. Here’s how it works:<\/p>\n\n\n\n For this example, we’ll be blinking the ESP32 onboard LED. In our case, it’s connected to GPIO 2. Other ESP32 boards might have the built-in LED connected to a different GPIO.<\/p>\n\n\n\n Alternatively, you can actually wire a physical LED via a 220 Ohm resistor to your board.<\/p>\n\n\n\n Parts Required:<\/strong><\/p>\n\n\n\n You can use the preceding links or go directly to MakerAdvisor.com\/tools<\/a> to find all the parts for your projects at the best price!<\/p> The following code uses periodic FreeRTOS timers to blink the ESP32 onboard LED. You can upload it to your ESP32 board.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n Start by defining the GPIO connected to the LED. Change if you’re using a different GPIO pin.<\/p>\n\n\n\n Create a handler for the timer. A handler is like a name that we use to refer to the timer. At first, we set it to NULL<\/span> because we haven’t created the actual timer yet. We’ll call the timer handler blinkTimer<\/span>.<\/p>\n\n\n\n Create a variable called ledState<\/span> to hold the current state of the LED. When the program first runs, the LED is turned off (false<\/span>).<\/p>\n\n\n\n The BlinkCallback<\/span> is the function we’ll want to run periodically. It should accept a parameter of type TimerHandle_t<\/span>.<\/p>\n\n\n\n We first invert the current LED state:<\/p>\n\n\n\n Then, we turn the LED on or off accordingly using the digitalWrite()<\/span> function.<\/p>\n\n\n\n In the setup()<\/span>, initialize the Serial Monitor and set up the LED as an OUTPUT<\/span>.<\/p>\n\n\n\n Then, create the timer, blinkTimer<\/span>, using the xTimeCreate()<\/span> function we’ve seen in the introduction section. This timer, once started, will call the BlinkCallback<\/span> function every 1000 milliseconds (1 second).<\/p>\n\n\n\n We also check if the timer was successfully created. If it fails to be created, it will return NULL<\/span>.<\/p>\n\n\n\n Finally, we can start our blinkTimer<\/span> by calling the xTimerStart()<\/span> function. The timer will start immediately (the second argument of the function is 0<\/span>).<\/p>\n\n\n\n The loop()<\/span> is empty because the FreeRTOS scheduler takes care of keeping the program running, waiting for the timer interrupts and tasks. However, if it is required for your project, you can add any code you need to the loop()<\/span>.<\/p>\n\n\n\n Upload the code to your ESP32 board.<\/p>\n\n\n\n Then, open the Serial Monitor at a baud rate of 115200.<\/p>\n\n\n\n The ESP32 on-board LED will start blinking every second (or the LED connected to GPIO 2).<\/p>\n\n\n\n The Serial Monitor will show the current state of the LED (note that the built-in LED of the ESP32 works with inverted logic).<\/p>\n\n\n As you can see, using FreeRTOS periodic timers is quite simple, useful, and practical to use in your projects. For example, besides blinking an LED, you can use it for periodic tasks like getting data from a sensor, sending data to a server, logging data to a microSD card, checking the state of an input, and much more.<\/p>\n\n\n\n After understanding how to create a periodic timer, it is quite simple to create multiple timers if you need to run multiple tasks periodically with the same or different intervals.<\/p>\n\n\n\n To show you how to do that, we’ll create a new example that blinks two LEDs at different frequencies. We’ll create two periodic timers, one to control each LED.<\/p>\n\n\n\n For this example, connect two LEDs to your ESP32 board via a 220 Ohm resistor. We’re connecting the LEDs to GPIOs 2 and 4, but you can use any other suitable pins. Just make sure to modify the code accordingly.<\/p>\n\n\n\n Parts Required:<\/strong><\/p>\n\n\n\n Recommended reading: ESP32 Pinout Reference: Which GPIO pins should you use?<\/a><\/p>\n\n\n\n Upload the following code to your ESP32 board.<\/p>\n\n\n View raw code<\/a><\/p>\n\n\n\n If you’ve understood how to create a timer in the previous example, you’ll see that it is quite simple to create multiple timers.<\/p>\n\n\n\n We define the GPIOs to control each of the LEDs.<\/p>\n\n\n\n Then, we create a time handler for each timer. Each timer will control a different LED.<\/p>\n\n\n\n We create a callback function that will be called after each timer to control each of the LEDs.<\/p>\n\n\n\n In the setup()<\/span>, we can actually create the timers to blink each of the LEDs. The following timer will call the BlinkRedCallback<\/span> function every 700 milliseconds, which will result in the Red LED toggling its state every 700 milliseconds.<\/p>\n\n\n\n We also create a timer to control the other LED. This timer will call the BlinkBlueCallback<\/span> function every 1100 milliseconds.<\/p>\n\n\n\n Finally, we can start the timers by calling the xTimerStart()<\/span> function.<\/p>\n\n\n\n The loop()<\/span> is empty because the FreeRTOS scheduler will take care of running the timers at the appropriate time. If you need, you can add code to the loop()<\/span> for any other tasks you need for your project.<\/p>\n\n\n\n Upload the previous code to your ESP32 board.<\/p>\n\n\n\n This will result in two LEDs blinking at different frequencies.<\/p>\n\n\n\n You can also open the Serial Monitor to check the results.<\/p>\n\n\n One-shot timers will trigger a callback function once after a predefined period. This allows you to run a specific task after a predefined time.<\/p>\n\n\n To show you how one-shot timers work, we’ll create a simple example in which we’ll toggle the state of an LED five seconds after pressing a pushbutton.<\/p>\n\n\n\n Here’s how it works:<\/p>\n\n\n\n For this example, connect an LED and a pushbutton to the ESP32 GPIOs. We’re connecting the LED to GPIO 2 and the pushbutton to GPIO 4. We’re not using any resistor with the pushbutton because we’ll use the ESP32’s internal pull-up resistor.<\/p>\n\n\n\n Parts Required:<\/strong><\/p>\n\n\n\n Upload the following code to your ESP32 board.<\/p>\n\n\n\n
Table of Contents<\/h2>\n\n\n\n
\n
\n
\n
\n
Timer Interrupts\/Software Timers<\/h2>\n\n\n\n
![\"Timer](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2018\/07\/alarm-clock-1-150x150.png?resize=150%2C150&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\n
FreeRTOS Timers Basics<\/h3>\n\n\n\n
Creating a Timer<\/h4>\n\n\n\n
\n
xTimerCreate(\n \"BlinkTimer\", \/\/ Timer name\n 1000 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkCallback \/\/ Callback function\n);<\/code><\/pre>\n\n\n\nStarting a Timer<\/h4>\n\n\n\n
Stopping a Timer<\/h4>\n\n\n\n
Resetting a Timer<\/h4>\n\n\n\n
Starting a Timer in ISRs (interrupt service routines)<\/h4>\n\n\n\n
\n\n\n\nFreeRTOS Periodic Timer with the ESP32<\/h2>\n\n\n\n
![\"Two](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-FreeRTOS-Software-Timers-Examples.jpg?resize=750%2C421&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n1) Blinking an LED with a Periodic Timer<\/h3>\n\n\n\n
\n
Circuit Diagram<\/h4>\n\n\n\n
\n
![](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/10\/header-200.png?w=1200&quality=100&strip=all&ssl=1\")
<\/a><\/p>\n\n\n![\"Circuit](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-with-LED_circuit-diagram.png?resize=751%2C825&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nCode<\/h4>\n\n\n\n
\/*\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-freertos-software-timers-interrupts\/\n Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.\n The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.\n*\/\n#include <Arduino.h>\n\n#define LED_PIN 2\n\nTimerHandle_t blinkTimer = NULL;\n\nbool ledState = false;\n\nvoid BlinkCallback(TimerHandle_t xTimer) {\n ledState = !ledState;\n \n if (ledState) {\n digitalWrite(LED_PIN, HIGH);\n Serial.print("LED is ");\n Serial.println("ON");\n } else {\n digitalWrite(LED_PIN, LOW);\n Serial.print("LED is ");\n Serial.println("OFF");\n }\n}\n\nvoid setup() {\n Serial.begin(115200);\n delay(1000);\n Serial.println("Starting FreeRTOS");\n Serial.println("Periodic Timer for LED Blink");\n\n pinMode(LED_PIN, OUTPUT);\n\n blinkTimer = xTimerCreate(\n "BlinkTimer", \/\/ Timer name\n 1000 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkCallback \/\/ Callback function\n );\n if (blinkTimer == NULL) {\n Serial.println("Failed to create timer!");\n while (1);\n }\n\n xTimerStart(blinkTimer, 0); \/\/ Start timer immediately\n}\n\nvoid loop() {\n \/\/ Empty\n}\n<\/code><\/pre>\n\tHow Does the Code Work?<\/h4>\n\n\n\n
#define LED_PIN 2<\/code><\/pre>\n\n\n\nTimerHandle_t blinkTimer = NULL;<\/code><\/pre>\n\n\n\nbool ledState = false;<\/code><\/pre>\n\n\n\nTimer Callback Function<\/strong><\/h5>\n\n\n\n
void BlinkCallback(TimerHandle_t xTimer) {\n ledState = !ledState;\n \n if (ledState) {\n digitalWrite(LED_PIN, HIGH);\n Serial.print(\"LED is \");\n Serial.println(\"ON\");\n } else {\n digitalWrite(LED_PIN, LOW);\n Serial.print(\"LED is \");\n Serial.println(\"OFF\");\n }\n}<\/code><\/pre>\n\n\n\nledState = !ledState;<\/code><\/pre>\n\n\n\nif (ledState) {\n digitalWrite(LED_PIN, HIGH);\n Serial.print(\"LED is \");\n Serial.println(\"ON\");\n} else {\n digitalWrite(LED_PIN, LOW);\n Serial.print(\"LED is \");\n Serial.println(\"OFF\");\n}<\/code><\/pre>\n\n\n\nsetup()<\/strong><\/h5>\n\n\n\n
void setup() {\n Serial.begin(115200);\n delay(1000);\n Serial.println(\"Starting FreeRTOS\");\n Serial.println(\"Periodic Timer for LED Blink\");\n\n pinMode(LED_PIN, OUTPUT);<\/code><\/pre>\n\n\n\nCreating the Timer<\/strong><\/h5>\n\n\n\n
blinkTimer = xTimerCreate(\n \"BlinkTimer\", \/\/ Timer name\n 1000 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkCallback \/\/ Callback function\n);<\/code><\/pre>\n\n\n\nif (blinkTimer == NULL) {\n Serial.println(\"Failed to create timer!\");\n while (1);\n}<\/code><\/pre>\n\n\n\nStarting the Timer<\/strong><\/h5>\n\n\n\n
xTimerStart(blinkTimer, 0); \/\/ Start timer immediately<\/code><\/pre>\n\n\n\nloop()<\/strong><\/h5>\n\n\n\n
void loop() {\n \/\/ Empty\n}<\/code><\/pre>\n\n\n\nDemonstration<\/h4>\n\n\n\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2020\/04\/ESP32-board-Built_in-LED-turned-on-HIGH.jpg?ssl=1\")
<\/figure><\/div>![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2020\/04\/ESP32-board-Built_in-LED-turned-off-LOW.jpg?ssl=1\")
<\/figure><\/div><\/div><\/div><\/div><\/div>\n\n\n\n![\"Serial](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/Blink-LED-freertos-periodic-timer-demonstration-serial-monitor.png?resize=749%2C318&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n2) Blinking Multiple LEDs at Different Frequencies<\/h3>\n\n\n\n
Circuit Diagram<\/h4>\n\n\n\n
\n
![\"Circuit](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-with-two-LEDs_bb.png?resize=709%2C826&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nCode<\/h4>\n\n\n\n
\/*\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-freertos-software-timers-interrupts\/\n Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.\n The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.\n*\/\n#define LED_PIN_RED 2\n#define LED_PIN_BLUE 4\n\nTimerHandle_t blinkTimerRed = NULL;\nTimerHandle_t blinkTimerBlue = NULL;\n\nbool ledStateRed = false;\nbool ledStateBlue = false;\n\nvoid BlinkRedCallback(TimerHandle_t xTimer) {\n ledStateRed = !ledStateRed;\n \n if (ledStateRed) {\n digitalWrite(LED_PIN_RED, HIGH);\n Serial.print("Red LED is ");\n Serial.println("ON");\n } else {\n digitalWrite(LED_PIN_RED, LOW);\n Serial.print("Red LED is ");\n Serial.println("OFF");\n }\n}\n\nvoid BlinkBlueCallback(TimerHandle_t xTimer) {\n ledStateBlue = !ledStateBlue;\n \n if (ledStateBlue) {\n digitalWrite(LED_PIN_BLUE, HIGH);\n Serial.print("Blue LED is ");\n Serial.println("ON");\n } else {\n digitalWrite(LED_PIN_BLUE, LOW);\n Serial.print("Blue LED is ");\n Serial.println("OFF");\n }\n}\n\nvoid setup() {\n Serial.begin(115200);\n delay(1000);\n Serial.println("Starting FreeRTOS");\n Serial.println("Periodic Timers for Two LEDs");\n\n pinMode(LED_PIN_RED, OUTPUT);\n pinMode(LED_PIN_BLUE, OUTPUT);\n\n blinkTimerRed = xTimerCreate(\n "BlinkTimerRed", \/\/ Timer name\n 700 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkRedCallback \/\/ Callback function\n );\n if (blinkTimerRed == NULL) {\n Serial.println("Failed to create blinkTimerRed timer!");\n while (1);\n }\n\n blinkTimerBlue = xTimerCreate(\n "BlinkTimerBlue", \/\/ Timer name\n 1100 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkBlueCallback \/\/ Callback function\n );\n if (blinkTimerBlue == NULL) {\n Serial.println("Failed to create blinkTimerBlue timer!");\n while (1);\n }\n\n xTimerStart(blinkTimerRed, 0); \/\/ Start timer immediately\n xTimerStart(blinkTimerBlue, 0); \/\/ Start timer immediately\n}\n\nvoid loop() {\n \/\/ Empty\n}\n<\/code><\/pre>\n\tHow Does the Code Work?<\/h4>\n\n\n\n
#define LED_PIN_RED 2\n#define LED_PIN_BLUE 4<\/code><\/pre>\n\n\n\nTimerHandle_t blinkTimerRed = NULL;\nTimerHandle_t blinkTimerBlue = NULL;<\/code><\/pre>\n\n\n\nvoid BlinkRedCallback(TimerHandle_t xTimer) {\n ledStateRed = !ledStateRed;\n \n if (ledStateRed) {\n digitalWrite(LED_PIN_RED, HIGH);\n Serial.print(\"Red LED is \");\n Serial.println(\"ON\");\n } else {\n digitalWrite(LED_PIN_RED, LOW);\n Serial.print(\"Red LED is \");\n Serial.println(\"OFF\");\n }\n}\n\nvoid BlinkBlueCallback(TimerHandle_t xTimer) {\n ledStateBlue = !ledStateBlue;\n \n if (ledStateBlue) {\n digitalWrite(LED_PIN_BLUE, HIGH);\n Serial.print(\"Blue LED is \");\n Serial.println(\"ON\");\n } else {\n digitalWrite(LED_PIN_BLUE, LOW);\n Serial.print(\"Blue LED is \");\n Serial.println(\"OFF\");\n }\n}<\/code><\/pre>\n\n\n\nblinkTimerRed = xTimerCreate(\n \"BlinkTimerRed\", \/\/ Timer name\n 700 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkRedCallback \/\/ Callback function\n);\nif (blinkTimerRed == NULL) {\n Serial.println(\"Failed to create blinkTimerRed timer!\");\n while (1);\n}<\/code><\/pre>\n\n\n\nblinkTimerBlue = xTimerCreate(\n \"BlinkTimerBlue\", \/\/ Timer name\n 1100 \/ portTICK_PERIOD_MS, \/\/ 1s period\n pdTRUE, \/\/ Auto-reload (periodic timer)\n NULL, \/\/ Timer ID\n BlinkBlueCallback \/\/ Callback function\n);\nif (blinkTimerBlue == NULL) {\n Serial.println(\"Failed to create blinkTimerBlue timer!\");\n while (1);\n}<\/code><\/pre>\n\n\n\nxTimerStart(blinkTimerRed, 0); \/\/ Start timer immediately\nxTimerStart(blinkTimerBlue, 0); \/\/ Start timer immediately<\/code><\/pre>\n\n\n\nvoid loop() {\n \/\/ Empty\n}<\/code><\/pre>\n\n\n\nDemonstration<\/h4>\n\n\n\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-FreeRTOS-Timers-Blink-LEDs-at-different-frequencies.jpg?ssl=1\")
<\/figure><\/div>![\"\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-FreeRTOS-Software-Timers-Examples.jpg?ssl=1\")
<\/figure><\/div><\/div><\/div><\/div><\/div>\n\n\n\n![\"Serial](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/Blink-Two-LEDs-different-frequencies-freertos-timers-serial-monitor-demonstration.png?resize=666%2C315&quality=100&strip=all&ssl=1\")
<\/a><\/figure><\/div>\n\n\n
\n\n\n\nFreeRTOS One-Shot Timers with the ESP32<\/h2>\n\n\n\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-connected-to-led-and-pushbutton.jpg?resize=750%2C422&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n1) Toggle an LED with a Pushbutton (with a delay)<\/h3>\n\n\n\n
\n
Circuit Diagram<\/h4>\n\n\n\n
\n
![\"ESP32](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2025\/10\/ESP32-with-LED-and-pushbutton_bb.png?resize=729%2C847&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\nCode<\/h4>\n\n\n\n
\/*\n Rui Santos & Sara Santos - Random Nerd Tutorials\n Complete project details at https:\/\/RandomNerdTutorials.com\/esp32-freertos-software-timers-interrupts\/\n Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.\n The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.\n*\/\n#define BUTTON_PIN 4\n#define LED_PIN 2\n#define DEBOUNCE_DELAY 200\n#define TIMER_DELAY 5000\n\nTimerHandle_t toggleTimer = NULL;\nvolatile uint32_t lastInterruptTime = 0;\nvolatile bool ledState = false;\n\nvoid IRAM_ATTR buttonISR() {\n uint32_t currentTime = millis();\n if (currentTime - lastInterruptTime > DEBOUNCE_DELAY) {\n BaseType_t higherPriorityTaskWoken = pdFALSE;\n xTimerStartFromISR(toggleTimer, &higherPriorityTaskWoken);\n Serial.print("buttonISR: LED will ");\n if (ledState) {\n Serial.print("turn OFF");\n } else {\n Serial.print("turn ON");\n }\n Serial.print(" in 5 seconds");\n Serial.println();\n lastInterruptTime = currentTime;\n if (higherPriorityTaskWoken) {\n portYIELD_FROM_ISR();\n }\n }\n}\n\nvoid ToggleCallback(TimerHandle_t xTimer) {\n ledState = !ledState;\n if (ledState) {\n digitalWrite(LED_PIN, HIGH);\n Serial.println("LED is ON");\n } else {\n digitalWrite(LED_PIN, LOW);\n Serial.println("LED is OFF");\n }\n}\n\nvoid setup() {\n Serial.begin(115200);\n delay(1000);\n Serial.println("Starting FreeRTOS");\n\n pinMode(BUTTON_PIN, INPUT_PULLUP);\n pinMode(LED_PIN, OUTPUT);\n attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), buttonISR, FALLING);\n\n toggleTimer = xTimerCreate(\n "ToggleTimer", \/\/ Timer name\n TIMER_DELAY \/ portTICK_PERIOD_MS, \/\/ 5s delay\n pdFALSE, \/\/ One-shot\n NULL, \/\/ Timer ID\n ToggleCallback \/\/ Callback\n );\n if (toggleTimer == NULL) {\n Serial.println("Failed to create timer!");\n while (1);\n }\n}\n\nvoid loop() {\n \/\/ Empty\n}\n<\/code><\/pre>\n\t