Espressif
docs.espressif.com › projects › arduino-esp32 › en › latest › api › timer.html
Timer - - — Arduino ESP32 latest documentation
/* Repeat timer example This example shows how to use hardware timer in ESP32. The timer calls onTimer function every second. The timer can be stopped with button attached to PIN 0 (IO0). This example code is in the public domain.
Espressif Docs
espressif-docs.readthedocs-hosted.com › projects › arduino-esp32 › en › latest › api › timer.html
Timer — Arduino-ESP32 2.0.14 documentation
/* Repeat timer example This example shows how to use hardware timer in ESP32. The timer calls onTimer function every second. The timer can be stopped with button attached to PIN 0 (IO0). This example code is in the public domain.
Hardware timer, how to run once and restart again?
I had some trouble with timers and alarms on my esp32 doit devboard. Spent many hours trying to debug, end of the days its a silicon issue with the REV0 chips. Not sure if this applies to you but more information can be found here: https://github.com/espressif/arduino-esp32/issues/1313 More on reddit.com
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April 12, 2021Hardware Timer ESP32 Dev Module
Nano ESP32 category you chose is only used for discussions directly related to the Arduino Nano ESP32 board · In the future, please take the time to pick the forum category that best suits the subject of your question. There is an "About the _____ category" topic at the top of each category ... More on forum.arduino.cc
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CircuitDigest
circuitdigest.com › microcontroller-projects › esp32-timers-and-timer-interrupts
ESP32 Timers & Timer Interrupt Tutorial
August 5, 2025 - For example, the speed of a timer in an ESP32, which is running at a clock frequency of 80MHz, will be 80MHz or 8000000Hz for a set prescaler value of 1 and will be 1MHz or 1000000Hz for a prescaler value of 80.
Espressif
docs.espressif.com › projects › esp-idf › en › v4.3 › esp32 › api-reference › peripherals › timer.html
General Purpose Timer - ESP32 - — ESP-IDF Programming Guide v4.3 documentation
Timer Control - describes how to ... use alarms. Interrupts- explains how to use interrupt callbacks. The two ESP32 timer groups, with two timers in each, provide the total of four individual timers for use....
ElectronicWings
electronicwings.com › esp32 › esp32-timer-interrupts
ESP32 Timer Interrupts | ESP32
ESP32 has only one inbuilt LED which shows the only status. Not connected to any GPIO pin · /* Timer Interrupt in ESP32, Alarm generation in ESP32 www.electronicwings.com */ #define LED_PIN 2 // In some ESP32 board have inbuilt LED volatile int interruptCounter; //for counting interrupt int totalInterruptCounter; //total interrupt counting int LED_STATE=LOW; hw_timer_t * timer = NULL; //H/W timer defining (Pointer to the Structure) portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED; void IRAM_ATTR onTimer() { //Defining Inerrupt function with IRAM_ATTR for faster access portENTER_CRITICAL_I
DeepBlue
deepbluembedded.com › home › blog › esp32 timers & timer interrupt tutorial (arduino ide)
ESP32 Timers & Timer Interrupt Tutorial (Arduino IDE) – DeepBlueMbedded
February 17, 2025 - Or just refer to the table for ... The ESP32 SoCs come with 4 hardware timers, each of which is a general-purpose 64-bit up/down counter with a 16-bit prescaler....
GitHub
github.com › khoih-prog › ESP32TimerInterrupt
GitHub - khoih-prog/ESP32TimerInterrupt: This library enables you to use Interrupt from Hardware Timers on an ESP32-based board. It now supports 16 ISR-based timers, while consuming only 1 hardware Timer. Timers' interval is very long (ulong millisecs). The most important feature is they're ISR-based timers. Therefore, their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. · GitHub
January 29, 2023 - This library enables you to use Interrupt from Hardware Timers on an ESP32-based board. It now supports 16 ISR-based timers, while consuming only 1 hardware Timer. Timers' interval is very long (ulong millisecs).
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Esp32developer
esp32developer.com › programming-in-c-c › timing › hardware-timers
Hardware Timers – ESP32 Developer
(divider x alarm_value)=Time period, so 1uS x 100 = 100uS timer_enable_intr(TIMER_GROUP_0, TIMER_0); timer_isr_register(TIMER_GROUP_0, TIMER_0, &timer_tg0_isr, NULL, 0, &s_timer_handle); timer_start(TIMER_GROUP_0, TIMER_0); } /* In your initialise function somewhere //----- CREATE OUR HARDWARE TIMER ----- timer_tg0_initialise(100); */
EmbeddedExplorer
embeddedexplorer.com › esp32-timer-tutorial
ESP32 Timers with ESP-IDF — EmbeddedExplorer
April 22, 2025 - ESP32 has four 64-bit general purpose timers, which are divided into two groups, each group has two timer instances. We will learn how to initialise a timer, configure timer duration, start a timer, and how to use timer interrupt.
Luis Llamas
luisllamas.es › inicio › tutoriales arduino › curso esp8266 / esp32
How to use ESP32 timers
November 25, 2024 - Depending on the ESP32 model, you will find 2 to 4 timers (but the usage is identical across all models).
Espressif
docs.espressif.com › projects › esp-idf › en › v4.4 › esp32 › api-reference › peripherals › timer.html
General Purpose Timer - ESP32 - — ESP-IDF Programming Guide v4.4 documentation
Timer Control - describes how to ... use alarms. Interrupts- explains how to use interrupt callbacks. The two ESP32 timer groups, with two timer(s) in each, provide the total of four individual timers for use....
Esp32
esp32.co.uk › testing-esp32-hardware-timers-with-interrupts-beginner-friendly-guide
ESP32 Hardware Timer Interrupts (Arduino) – Complete Guide + Example Code – Esp32.co.uk
November 18, 2025 - ESP32 microcontrollers include multiple hardware timers that can trigger interrupts with microsecond precision.
Espressif
docs.espressif.com › projects › esp-idf › en › stable › esp32 › api-reference › peripherals › gptimer.html
General Purpose Timer (GPTimer) - ESP32 - — ESP-IDF Programming Guide v6.0.2 documentation
GPTimer is a dedicated driver for the ESP32 [Timer Group peripheral]. This timer can select different clock sources and prescalers to meet the requirements of nanosecond-level resolution. Additionally, it has flexible timeout alarm functions and allows automatic updating of the count value ...
Random Nerd Tutorials
randomnerdtutorials.com › home › project › esp32 › esp32 with freertos: software timers/timer interrupts (arduino ide)
ESP32 FreeRTOS: Software Timers/Timer Interrupts (Arduino) | Random Nerd Tutorials
November 20, 2025 - Use software timers (timer interrupts) with the ESP32 using FreeRTOS programming on Arduino IDE. Discover auto-reload (periodic) timers and one-shot timers with simple examples.
Arduino
arduino.cc › reference › en › libraries › esp32timerinterrupt
Arduino
July 19, 2022 - The Arduino environment can be extended through the use of libraries. Libraries provide extra functionality for use in sketches. To use a library in a sketch, select it from Sketch > Import Library.
Arduino Libraries
arduinolibraries.info › libraries › esp32-timer-interrupt
ESP32TimerInterrupt - Arduino Libraries
November 16, 2022 - It now supports 16 ISR-based Timers, while consuming only 1 Hardware Timer. Timers interval is very long (ulong millisecs). The most important feature is they are ISR-based Timers. Therefore, their executions are not blocked by bad-behaving functions or tasks.
Reddit
reddit.com › r/esp32 › hardware timer, how to run once and restart again?
r/esp32 on Reddit: Hardware timer, how to run once and restart again?
April 12, 2021 -
Guys
I have a DevKitC dev board, and I'm trying to set up a HW timer that I want to re-use under certain conditions. In other words, I don't want it to reload automatically, it should run once and then remain dormant until I enable it again. It seems to work the first time, but when I enable the timer a second time it fires immediately, without any delay. It seems I'm not resetting it properly, so that the counter starts from 0 again (?).
What I've tried is this:
initialize timer 0 in setup(), with a prescaler for 80MHz.
myTimer = timerBegin (0, 80, true); timerAttachInterrupt (myTimer, &isrMyTimer, true);
then when I want to use the timer I enable it as follows (for a duration of 3 seconds):
timerAlarmWrite(myTimer, 3000000), false); timerAlarmEnable(myTimer);
I am also trying to confirm the frequency to use for the timer, whether it is indeed 80MHz. I get the values as shown below for the different functions. Any thoughts on what they mean?
getCpuFrequencyMhz() 240 getXtalFrequencyMhz() 40 getApbFrequency() 80000000
Top answer 1 of 4
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I had some trouble with timers and alarms on my esp32 doit devboard. Spent many hours trying to debug, end of the days its a silicon issue with the REV0 chips. Not sure if this applies to you but more information can be found here: https://github.com/espressif/arduino-esp32/issues/1313
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I managed to get it working. The trick that worked for me was to reset the timer (counter) before each use, with the following statement: timerRestart() Below is a little pseudo sketch, only showing the relevant statements, to give you or anyone finding this post later, an idea of what worked for me. #include // only needed to get ESP32 frequency detail hw_timer_t * tmrTEST = NULL; // timer used for TESTING unsigned long lngTimerStart = 0; // system micro-seconds at timer start int tmrDuration = 5; // run timer for 5 seconds // Interrupt Service Routine called when TEST timer fires. void IRAM_ATTR isrTimerTEST() { Serial.print(" >>>>> TEST TIMER ISR: "); Serial.print( micros() ); Serial.print(" diff="); Serial.println((micros()-lngTimerStart)/1000/1000); } void setup() { Serial.begin(115200); ... // Set up TEST timer.. tmrTEST = timerBegin (1, 80, true); // use ESP32 Timer 1, pre-scale 80 (for 80MHz freq), count up. timerAttachInterrupt (tmrTEST, &isrTimerTEST, true); // attach the function to call when timer interrupt fires. Edge. Serial.print(" >> CPU Freq: "); Serial.println(getCpuFrequencyMhz()); Serial.print(" >> XTL Freq: "); Serial.println(getXtalFrequencyMhz()); Serial.print(" >> APB Freq: "); Serial.println(getApbFrequency()); ... } void loop() { ... if (tmrDuration > 0) { // initiate TEST timer. duration in micro-seconds. False to run once. timerAlarmWrite(tmrTEST, (tmrDuration * 1000000), false); timerRestart(tmrTEST); // reset timer counter timerAlarmEnable(tmrTEST); // start the timer lngTimerStart = micros(); Serial.print(" >>>>> TimerTEST dur="); Serial.print(tmrDuration); Serial.print(" start: "); Serial.println( lngTimerStart ); } ... } Thanks for your replies and time !
Espressif Docs
espressif-docs.readthedocs-hosted.com › projects › esp-idf › en › stable › api-reference › peripherals › timer.html
Timer — ESP-IDF Programming Guide v4.1 documentation
To do that, set the TIMERGN.int_clr_timers.tM structure, defined in soc/esp32/include/soc/timer_group_struct.h. In this structure, N is the timer group number [0, 1], M is the timer number [0, 1]. For example, to clear an interrupt status bit for the timer 1 in the timer group 0, call the following: ... For more information on how to use interrupts, please see the application example below. The 64-bit hardware timer example: peripherals/timer_group.
Arduino Forum
forum.arduino.cc › projects › programming
Hardware Timer ESP32 Dev Module - Programming - Arduino Forum
July 19, 2024 - #include #include hw_timer_t *timer = NULL; const int ledPin = 2; void IRAM_ATTR onTimer() { // Toggle LED state digitalWrite(ledPin, !digitalRead(ledPin)); } void setup() { pinMode(ledPin, OUTPUT); // Initialize timer 0 with a frequency of 1 Hz timer = timerBegin(0, 1); // Attach an ISR function to the timer timerAttachInterrupt(timer, &onTimer, true); // Set an alarm to trigger after 1 second timerAlarmWrite(timer, 1000000, true); // 10...