ESP32_New_TimerInterrupt Library

Why do we need this ESP32_New_TimerInterrupt library
- Important Notes
- Features
- Why using ISR-based Hardware Timer Interrupt is better
- Currently supported Boards
- Important Notes about ISR
Changelog
Prerequisites
Installation
- Use Arduino Library Manager
- Manual Install
- VS Code & PlatformIO
HOWTO Fix Multiple Definitions Linker Error
HOWTO Use analogRead() with ESP32 running WiFi and/or BlueTooth (BT/BLE)
- 1. ESP32 has 2 ADCs, named ADC1 and ADC2
- 2. ESP32 ADCs functions
- 3. ESP32 WiFi uses ADC2 for WiFi functions
More useful Information
How to use
Examples
- 1. Argument_None
- 2. Change_Interval.
- 3. RPM_Measure
- 4. SwitchDebounce
- 5. TimerInterruptTest
- 6. ISR_16_Timers_Array
- 7. ISR_16_Timers_Array_Complex
Example ISR_16_Timers_Array_Complex
Debug Terminal Output Samples
- 1. TimerInterruptTest on ESP32C3_DEV
- 2. Change_Interval on ESP32_DEV
- 3. Argument_None on ESP32S2_DEV
- 4. ISR_16_Timers_Array_Complex on ESP32C3_DEV
- 5. ISR_16_Timers_Array on ESP32S2_DEV
- 6. ISR_16_Timers_Array_Complex on ESP32S3_DEV New
Debug
Troubleshooting
Issues
TO DO
DONE
Contributions and Thanks
Contributing
License
Copyright

Why do we need this ESP32_New_TimerInterrupt library

Important Notes

Avoid using PIN_D1 (GPIO1) in your code due to issue with core v2.0.0 and v2.0.1. Check ESP32 Core v2.0.1 / 2.0.1 RC1 crashes if using pinMode with GPIO1 #5868. Only OK with core v1.0.6-
Don't use float in ISR due to issue with core v2.0.0 and v2.0.1. Check ESP32 Core v2.0.1 / 2.0.1 RC1 crashes if using float in ISR #5892. Only OK with core v1.0.6-.

Features

This library enables you to use Interrupt from Hardware Timers on an ESP32, ESP32_S2/S3/C3-based board.

As Hardware Timers are rare, and very precious assets of any board, this library now enables you to use up to 16 ISR-based Timers, while consuming only 1 Hardware Timer. Timers' interval is very long (ulong millisecs).

Now with these new 16 ISR-based timers, the maximum interval is practically unlimited (limited only by unsigned long milliseconds) while the accuracy is nearly perfect compared to software timers.

The most important feature is they're ISR-based timers. Therefore, their executions are not blocked by bad-behaving functions / tasks. This important feature is absolutely necessary for mission-critical tasks.

The ISR_Timer_Complex example will demonstrate the nearly perfect accuracy compared to software timers by printing the actual elapsed millisecs of each type of timers.

Being ISR-based timers, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet and Blynk services. You can also have many (up to 16) timers to use.

This non-being-blocked important feature is absolutely necessary for mission-critical tasks.

You'll see blynkTimer Software is blocked while system is connecting to WiFi / Internet / Blynk, as well as by blocking task in loop(), using delay() function as an example. The elapsed time then is very unaccurate

Why using ISR-based Hardware Timer Interrupt is better

Imagine you have a system with a mission-critical function, measuring water level and control the sump pump or doing something much more important. You normally use a software timer to poll, or even place the function in loop(). But what if another function is blocking the loop() or setup().

So your function might not be executed, and the result would be disastrous.

You'd prefer to have your function called, no matter what happening with other functions (busy loop, bug, etc.).

The correct choice is to use a Hardware Timer with Interrupt to call your function.

These hardware timers, using interrupt, still work even if other functions are blocking. Moreover, they are much more precise (certainly depending on clock frequency accuracy) than other software timers using millis() or micros(). That's necessary if you need to measure some data requiring better accuracy.

Functions using normal software timers, relying on loop() and calling millis(), won't work if the loop() or setup() is blocked by certain operation. For example, certain function is blocking while it's connecting to WiFi or some services.

The catch is your function is now part of an ISR (Interrupt Service Routine), and must be lean / mean, and follow certain rules. More to read on:

HOWTO Attach Interrupt

Currently supported Boards

ESP32 boards, such as ESP32_DEV, etc.
ESP32_S2-based boards, such as ESP32S2_DEV, ESP32_S2 Saola, Adafruit QTPY_ESP32S2, ESP32S2 Native USB, UM FeatherS2 Neo, UM TinyS2, UM RMP, microS2, etc.
ESP32_C3-based boards, such as ESP32C3_DEV, LOLIN_C3_MINI, DFROBOT_BEETLE_ESP32_C3, ADAFRUIT_QTPY_ESP32C3, AirM2M_CORE_ESP32C3, XIAO_ESP32C3, etc. New
ESP32_S3-based boards, such as ESP32S3_DEV, ESP32_S3_BOX, UM TINYS3, UM PROS3, UM FEATHERS3, FEATHER_ESP32S3_NOPSRAM, QTPY_ESP32S3_NOPSRAM, etc. New

Important Notes about ISR

Inside the attached function, delay() won’t work and the value returned by millis() will not increment. Serial data received while in the function may be lost. You should declare as volatile any variables that you modify within the attached function.
Typically global variables are used to pass data between an ISR and the main program. To make sure variables shared between an ISR and the main program are updated correctly, declare them as volatile.

Prerequisites

Arduino IDE 1.8.19+ for Arduino.
ESP32 Core 2.0.5+ for ESP32-based boards (ESP32, ESP32_S2, ESP32_S3 and ESP32_C3). .

Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for ESP32_New_TimerInterrupt, then select / install the latest version. You can also use this link for more detailed instructions.

Manual Install

Another way to install is to:

Navigate to ESP32_New_TimerInterrupt page.
Download the latest release ESP32_New_TimerInterrupt-main.zip.
Extract the zip file to ESP32_New_TimerInterrupt-main directory
Copy whole ESP32_New_TimerInterrupt-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO

Install VS Code
Install PlatformIO
Install ESP32_New_TimerInterrupt library by using Library Manager. Search for ESP32_New_TimerInterrupt in Platform.io Author's Libraries
Use included platformio.ini file from examples to ensure that all dependent libraries will installed automatically. Please visit documentation for the other options and examples at Project Configuration File

HOWTO Fix `Multiple Definitions` Linker Error

The current library implementation, using xyz-Impl.h instead of standard xyz.cpp, possibly creates certain Multiple Definitions Linker error in certain use cases.

You can use

#include <ESP32_New_TimerInterrupt.hpp>               //https://github.com/khoih-prog/ESP32_New_TimerInterrupt

in many files. But be sure to use the following #include <ESP32_New_ISR_Timer.h> in just 1 .h, .cpp or .ino file, which must not be included in any other file, to avoid Multiple Definitions Linker Error

// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include <ESP32_New_TimerInterrupt.h>                //https://github.com/khoih-prog/ESP32_New_TimerInterrupt

HOWTO Use analogRead() with ESP32 running WiFi and/or BlueTooth (BT/BLE)

Please have a look at ESP_WiFiManager Issue 39: Not able to read analog port when using the autoconnect example to have more detailed description and solution of the issue.

1. ESP32 has 2 ADCs, named ADC1 and ADC2

2. ESP32 ADCs functions

ADC1 controls ADC function for pins GPIO32-GPIO39
ADC2 controls ADC function for pins GPIO0, 2, 4, 12-15, 25-27

3.. ESP32 WiFi uses ADC2 for WiFi functions

Look in file adc_common.c

In ADC2, there're two locks used for different cases:

lock shared with app and Wi-Fi: ESP32: When Wi-Fi using the ADC2, we assume it will never stop, so app checks the lock and returns immediately if failed. ESP32S2: The controller's control over the ADC is determined by the arbiter. There is no need to control by lock.

lock shared between tasks: when several tasks sharing the ADC2, we want to guarantee all the requests will be handled. Since conversions are short (about 31us), app returns the lock very soon, we use a spinlock to stand there waiting to do conversions one by one.

adc2_spinlock should be acquired first, then adc2_wifi_lock or rtc_spinlock.

In order to use ADC2 for other functions, we have to acquire complicated firmware locks and very difficult to do
So, it's not advisable to use ADC2 with WiFi/BlueTooth (BT/BLE).
Use ADC1, and pins GPIO32-GPIO39
If somehow it's a must to use those pins serviced by ADC2 (GPIO0, 2, 4, 12, 13, 14, 15, 25, 26 and 27), use the fix mentioned at the end of ESP_WiFiManager Issue 39: Not able to read analog port when using the autoconnect example to work with ESP32 WiFi/BlueTooth (BT/BLE).

More useful Information

The ESP32 has two timer groups, each one with two general purpose hardware timers. All the timers are based on 64 bits counters and 16 bit prescalers.

The timer counters can be configured to count up or down and support automatic reload and software reload.

They can also generate alarms when they reach a specific value, defined by the software. The value of the counter can be read by the software program.

Now with these new 16 ISR-based timers (while consuming only 1 hardware timer), the maximum interval is practically unlimited (limited only by unsigned long milliseconds). The accuracy is nearly perfect compared to software timers. The most important feature is they're ISR-based timers Therefore, their executions are not blocked by bad-behaving functions / tasks. This important feature is absolutely necessary for mission-critical tasks.

The ISR_Timer_Complex example will demonstrate the nearly perfect accuracy compared to software timers by printing the actual elapsed millisecs of each type of timers. Being ISR-based timers, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet and Blynk services. You can also have many (up to 16) timers to use. This non-being-blocked important feature is absolutely necessary for mission-critical tasks. You'll see blynkTimer Software is blocked while system is connecting to WiFi / Internet / Blynk, as well as by blocking task in loop(), using delay() function as an example. The elapsed time then is very unaccurate

How to use

Before using any Timer, you have to make sure the Timer has not been used by any other purpose.

Timer0, Timer1, Timer2 and Timer3 are supported for ESP32-S2.

Examples:

Example ISR_16_Timers_Array_Complex

ESP32_New_TimerInterrupt/examples/ISR_16_Timers_Array_Complex/ISR_16_Timers_Array_Complex.ino

Lines 43 to 383 in eb11f04

    
           #if !defined( ESP32 ) 
        
           	#error This code is intended to run on the ESP32 platform! Please check your Tools->Board setting. 
        
           #endif 
        
           // These define's must be placed at the beginning before #include "ESP32_New_TimerInterrupt.h" 
        
           #define _TIMERINTERRUPT_LOGLEVEL_     4 
        
           #include "ESP32_New_TimerInterrupt.h" 
        
           #include "ESP32_New_ISR_Timer.h" 
        
           #include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer 
        
           // Don't use PIN_D1 in core v2.0.0 and v2.0.1. Check https://github.com/espressif/arduino-esp32/issues/5868 
        
           #ifndef LED_BLUE 
        
           	#define LED_BLUE          25 
        
           #endif 
        
           #ifndef LED_RED 
        
           	#define LED_RED           27 
        
           #endif 
        
           // Don't use PIN_D1 in core v2.0.0 and v2.0.1. Check https://github.com/espressif/arduino-esp32/issues/5868 
        
           // Don't use PIN_D2 with ESP32_C3 (crash) 
        
           #define PIN_D19             19        // Pin D19 mapped to pin GPIO9 of ESP32 
        
           #define HW_TIMER_INTERVAL_US      10000L 
        
           volatile uint32_t startMillis = 0; 
        
           // Init ESP32 timer 1 
        
           ESP32Timer ITimer(1); 
        
           // Init ESP32_ISR_Timer 
        
           ESP32_ISR_Timer ISR_Timer; 
        
           #define LED_TOGGLE_INTERVAL_MS        2000L 
        
           // With core v2.0.0+, you can't use Serial.print/println in ISR or crash. 
        
           // and you can't use float calculation inside ISR 
        
           // Only OK in core v1.0.6- 
        
           bool IRAM_ATTR TimerHandler(void * timerNo) 
        
           { 
        
           	static bool toggle  = false; 
        
           	static int timeRun  = 0; 
        
           	ISR_Timer.run(); 
        
           	// Toggle LED every LED_TOGGLE_INTERVAL_MS = 2000ms = 2s 
        
           	if (++timeRun == ((LED_TOGGLE_INTERVAL_MS * 1000) / HW_TIMER_INTERVAL_US) ) 
        
           	{ 
        
           		timeRun = 0; 
        
           		//timer interrupt toggles pin PIN_D19 
        
           		digitalWrite(PIN_D19, toggle); 
        
           		toggle = !toggle; 
        
           	} 
        
           	return true; 
        
           } 
        
           ///////////////////////////////////////////////// 
        
           #define NUMBER_ISR_TIMERS         16 
        
           typedef void (*irqCallback)  (); 
        
           ///////////////////////////////////////////////// 
        
           #define USE_COMPLEX_STRUCT      true 
        
           #if USE_COMPLEX_STRUCT 
        
           typedef struct 
        
           { 
        
           	irqCallback   irqCallbackFunc; 
        
           	uint32_t      TimerInterval; 
        
           	unsigned long deltaMillis; 
        
           	unsigned long previousMillis; 
        
           } ISRTimerData; 
        
           // In NRF52, avoid doing something fancy in ISR, for example Serial.print() 
        
           // The pure simple Serial.prints here are just for demonstration and testing. Must be eliminate in working environment 
        
           // Or you can get this run-time error / crash 
        
           void doingSomething(int index); 
        
           #else 
        
           volatile unsigned long deltaMillis    [NUMBER_ISR_TIMERS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; 
        
           volatile unsigned long previousMillis [NUMBER_ISR_TIMERS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; 
        
           // You can assign any interval for any timer here, in milliseconds 
        
           uint32_t TimerInterval[NUMBER_ISR_TIMERS] = 
        
           { 
        
           	5000L,  10000L,  15000L,  20000L,  25000L,  30000L,  35000L,  40000L, 
        
           	45000L, 50000L,  55000L,  60000L,  65000L,  70000L,  75000L,  80000L 
        
           }; 
        
           void doingSomething(int index) 
        
           { 
        
           	unsigned long currentMillis  = millis(); 
        
           	deltaMillis[index]    = currentMillis - previousMillis[index]; 
        
           	previousMillis[index] = currentMillis; 
        
           } 
        
           #endif 
        
           //////////////////////////////////// 
        
           // Shared 
        
           //////////////////////////////////// 
        
           void doingSomething0() 
        
           { 
        
           	doingSomething(0); 
        
           } 
        
           void doingSomething1() 
        
           { 
        
           	doingSomething(1); 
        
           } 
        
           void doingSomething2() 
        
           { 
        
           	doingSomething(2); 
        
           } 
        
           void doingSomething3() 
        
           { 
        
           	doingSomething(3); 
        
           } 
        
           void doingSomething4() 
        
           { 
        
           	doingSomething(4); 
        
           } 
        
           void doingSomething5() 
        
           { 
        
           	doingSomething(5); 
        
           } 
        
           void doingSomething6() 
        
           { 
        
           	doingSomething(6); 
        
           } 
        
           void doingSomething7() 
        
           { 
        
           	doingSomething(7); 
        
           } 
        
           void doingSomething8() 
        
           { 
        
           	doingSomething(8); 
        
           } 
        
           void doingSomething9() 
        
           { 
        
           	doingSomething(9); 
        
           } 
        
           void doingSomething10() 
        
           { 
        
           	doingSomething(10); 
        
           } 
        
           void doingSomething11() 
        
           { 
        
           	doingSomething(11); 
        
           } 
        
           void doingSomething12() 
        
           { 
        
           	doingSomething(12); 
        
           } 
        
           void doingSomething13() 
        
           { 
        
           	doingSomething(13); 
        
           } 
        
           void doingSomething14() 
        
           { 
        
           	doingSomething(14); 
        
           } 
        
           void doingSomething15() 
        
           { 
        
           	doingSomething(15); 
        
           } 
        
           #if USE_COMPLEX_STRUCT 
        
           ISRTimerData curISRTimerData[NUMBER_ISR_TIMERS] = 
        
           { 
        
           	//irqCallbackFunc, TimerInterval, deltaMillis, previousMillis 
        
           	{ doingSomething0,    5000L, 0, 0 }, 
        
           	{ doingSomething1,   10000L, 0, 0 }, 
        
           	{ doingSomething2,   15000L, 0, 0 }, 
        
           	{ doingSomething3,   20000L, 0, 0 }, 
        
           	{ doingSomething4,   25000L, 0, 0 }, 
        
           	{ doingSomething5,   30000L, 0, 0 }, 
        
           	{ doingSomething6,   35000L, 0, 0 }, 
        
           	{ doingSomething7,   40000L, 0, 0 }, 
        
           	{ doingSomething8,   45000L, 0, 0 }, 
        
           	{ doingSomething9,   50000L, 0, 0 }, 
        
           	{ doingSomething10,  55000L, 0, 0 }, 
        
           	{ doingSomething11,  60000L, 0, 0 }, 
        
           	{ doingSomething12,  65000L, 0, 0 }, 
        
           	{ doingSomething13,  70000L, 0, 0 }, 
        
           	{ doingSomething14,  75000L, 0, 0 }, 
        
           	{ doingSomething15,  80000L, 0, 0 } 
        
           }; 
        
           void doingSomething(int index) 
        
           { 
        
           	unsigned long currentMillis  = millis(); 
        
           	curISRTimerData[index].deltaMillis    = currentMillis - curISRTimerData[index].previousMillis; 
        
           	curISRTimerData[index].previousMillis = currentMillis; 
        
           } 
        
           #else 
        
           irqCallback irqCallbackFunc[NUMBER_ISR_TIMERS] = 
        
           { 
        
           	doingSomething0,  doingSomething1,  doingSomething2,  doingSomething3, 
        
           	doingSomething4,  doingSomething5,  doingSomething6,  doingSomething7, 
        
           	doingSomething8,  doingSomething9,  doingSomething10, doingSomething11, 
        
           	doingSomething12, doingSomething13, doingSomething14, doingSomething15 
        
           }; 
        
           #endif 
        
           /////////////////////////////////////////// 
        
           #define SIMPLE_TIMER_MS        2000L 
        
           // Init SimpleTimer 
        
           SimpleTimer simpleTimer; 
        
           // Here is software Timer, you can do somewhat fancy stuffs without many issues. 
        
           // But always avoid 
        
           // 1. Long delay() it just doing nothing and pain-without-gain wasting CPU power.Plan and design your code / strategy ahead 
        
           // 2. Very long "do", "while", "for" loops without predetermined exit time. 
        
           void simpleTimerDoingSomething2s() 
        
           { 
        
           	static unsigned long previousMillis = startMillis; 
        
           	unsigned long currMillis = millis(); 
        
           	Serial.print(F("SimpleTimer : ")); 
        
           	Serial.print(SIMPLE_TIMER_MS / 1000); 
        
           	Serial.print(F(", ms : ")); 
        
           	Serial.print(currMillis); 
        
           	Serial.print(F(", Dms : ")); 
        
           	Serial.println(currMillis - previousMillis); 
        
           	for (uint16_t i = 0; i < NUMBER_ISR_TIMERS; i++) 
        
           	{ 
        
           #if USE_COMPLEX_STRUCT 
        
           		Serial.print(F("Timer : ")); 
        
           		Serial.print(i); 
        
           		Serial.print(F(", programmed : ")); 
        
           		Serial.print(curISRTimerData[i].TimerInterval); 
        
           		Serial.print(F(", actual : ")); 
        
           		Serial.println(curISRTimerData[i].deltaMillis); 
        
           #else 
        
           		Serial.print(F("Timer : ")); 
        
           		Serial.print(i); 
        
           		Serial.print(F(", programmed : ")); 
        
           		Serial.print(TimerInterval[i]); 
        
           		Serial.print(F(", actual : ")); 
        
           		Serial.println(deltaMillis[i]); 
        
           #endif 
        
           	} 
        
           	previousMillis = currMillis; 
        
           } 
        
           void setup() 
        
           { 
        
           	pinMode(PIN_D19, OUTPUT); 
        
           	Serial.begin(115200); 
        
           	while (!Serial && millis() < 5000); 
        
             delay(500); 
        
           	Serial.print(F("\nStarting ISR_16_Timers_Array_Complex on ")); 
        
           	Serial.println(ARDUINO_BOARD); 
        
           	Serial.println(ESP32_NEW_TIMERINTERRUPT_VERSION); 
        
           	Serial.print(F("CPU Frequency = ")); 
        
           	Serial.print(F_CPU / 1000000); 
        
           	Serial.println(F(" MHz")); 
        
           	// Interval in microsecs 
        
           	if (ITimer.attachInterruptInterval(HW_TIMER_INTERVAL_US, TimerHandler)) 
        
           	{ 
        
           		startMillis = millis(); 
        
           		Serial.print(F("Starting ITimer OK, millis() = ")); 
        
           		Serial.println(startMillis); 
        
           	} 
        
           	else 
        
           		Serial.println(F("Can't set ITimer. Select another freq. or timer")); 
        
           	startMillis = millis(); 
        
           	// Just to demonstrate, don't use too many ISR Timers if not absolutely necessary 
        
           	// You can use up to 16 timer for each ISR_Timer 
        
           	for (uint16_t i = 0; i < NUMBER_ISR_TIMERS; i++) 
        
           	{ 
        
           #if USE_COMPLEX_STRUCT 
        
           		curISRTimerData[i].previousMillis = startMillis; 
        
           		ISR_Timer.setInterval(curISRTimerData[i].TimerInterval, curISRTimerData[i].irqCallbackFunc); 
        
           #else 
        
           		previousMillis[i] = millis(); 
        
           		ISR_Timer.setInterval(TimerInterval[i], irqCallbackFunc[i]); 
        
           #endif 
        
           	} 
        
           	// You need this timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary. 
        
           	simpleTimer.setInterval(SIMPLE_TIMER_MS, simpleTimerDoingSomething2s); 
        
           } 
        
           #define BLOCKING_TIME_MS      10000L 
        
           void loop() 
        
           { 
        
           	// This unadvised blocking task is used to demonstrate the blocking effects onto the execution and accuracy to Software timer 
        
           	// You see the time elapse of ISR_Timer still accurate, whereas very unaccurate for Software Timer 
        
           	// The time elapse for 2000ms software timer now becomes 3000ms (BLOCKING_TIME_MS) 
        
           	// While that of ISR_Timer is still prefect. 
        
           	delay(BLOCKING_TIME_MS); 
        
           	// You need this Software timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary 
        
           	// You don't need to and never call ISR_Timer.run() here in the loop(). It's already handled by ISR timer. 
        
           	simpleTimer.run(); 
        
           }

Debug Terminal Output Samples

1. TimerInterruptTest on ESP32C3_DEV

The following is the sample terminal output when running example TimerInterruptTest to demonstrate how to start/stop Hardware Timers.

Starting TimerInterruptTest on ESP32_DEV
ESP32_New_TimerInterrupt v1.5.0
CPU Frequency = 240 MHz
[TISR] ESP32_TimerInterrupt: _timerNo = 0 , _fre = 1000000
[TISR] TIMER_BASE_CLK = 80000000 , TIMER_DIVIDER = 80
[TISR] _timerIndex = 0 , _timerGroup = 0
[TISR] _count = 0 - 1000000
[TISR] timer_set_alarm_value = 1000000.00
Starting  ITimer0 OK, millis() = 158
[TISR] ESP32_TimerInterrupt: _timerNo = 1 , _fre = 1000000
[TISR] TIMER_BASE_CLK = 80000000 , TIMER_DIVIDER = 80
[TISR] _timerIndex = 1 , _timerGroup = 0
[TISR] _count = 0 - 3000000
[TISR] timer_set_alarm_value = 3000000.00
Starting  ITimer1 OK, millis() = 189
Stop ITimer0, millis() = 5001
Start ITimer0, millis() = 10002
Stop ITimer1, millis() = 15001
Stop ITimer0, millis() = 15003
Start ITimer0, millis() = 20004
Stop ITimer0, millis() = 25005
Start ITimer1, millis() = 30002
Start ITimer0, millis() = 30006

2. Change_Interval on ESP32_DEV

The following is the sample terminal output when running example Change_Interval to demonstrate how to change Timer Interval on-the-fly

Starting Change_Interval on ESP32_DEV
ESP32_New_TimerInterrupt v1.5.0
CPU Frequency = 240 MHz
Starting  ITimer0 OK, millis() = 136
Starting  ITimer1 OK, millis() = 147
Time = 10001, Timer0Count = 5, Timer1Count = 2
Time = 20002, Timer0Count = 10, Timer1Count = 4
Changing Interval, Timer0 = 4000,  Timer1 = 10000
Time = 30003, Timer0Count = 12, Timer1Count = 5
Time = 40004, Timer0Count = 15, Timer1Count = 6
Changing Interval, Timer0 = 2000,  Timer1 = 5000
Time = 50005, Timer0Count = 20, Timer1Count = 8
Time = 60006, Timer0Count = 25, Timer1Count = 10
Changing Interval, Timer0 = 4000,  Timer1 = 10000
Time = 70007, Timer0Count = 27, Timer1Count = 11
Time = 80008, Timer0Count = 30, Timer1Count = 12
Changing Interval, Timer0 = 2000,  Timer1 = 5000
Time = 90009, Timer0Count = 35, Timer1Count = 14
Time = 100010, Timer0Count = 40, Timer1Count = 16
Changing Interval, Timer0 = 4000,  Timer1 = 10000

3. Argument_None on ESP32S2_DEV

The following is the sample terminal output when running example Argument_None

Starting Argument_None on ESP32S2_DEV
ESP32_New_TimerInterrupt v1.5.0
CPU Frequency = 240 MHz
[TISR] ESP32_S2_TimerInterrupt: _timerNo = 0 , _fre = 1000000
[TISR] TIMER_BASE_CLK = 80000000 , TIMER_DIVIDER = 80
[TISR] _timerIndex = 0 , _timerGroup = 0
[TISR] _count = 0 - 1000000
[TISR] timer_set_alarm_value = 1000000.00
ITimer0: millis() = 656
Starting  ITimer0 OK, millis() = 660
[TISR] ESP32_S2_TimerInterrupt: _timerNo = 1 , _fre = 1000000
[TISR] TIMER_BASE_CLK = 80000000 , TIMER_DIVIDER = 80
[TISR] _timerIndex = 1 , _timerGroup = 0
[TISR] _count = 0 - 5000000
[TISR] timer_set_alarm_value = 5000000.00
ITimer1: millis() = 682
Starting  ITimer1 OK, millis() = 685
ITimer0: millis() = 1651
ITimer0: millis() = 2651
ITimer0: millis() = 3651
ITimer0: millis() = 4651
ITimer0: millis() = 5651
ITimer1: millis() = 5676
ITimer0: millis() = 6651
ITimer0: millis() = 7651
ITimer0: millis() = 8651
ITimer0: millis() = 9651
ITimer0: millis() = 10651
ITimer1: millis() = 10676
ITimer0: millis() = 11651
ITimer0: millis() = 12651
ITimer0: millis() = 13651
ITimer0: millis() = 14651
ITimer0: millis() = 15651
ITimer1: millis() = 15676
ITimer0: millis() = 16651
ITimer0: millis() = 17651
ITimer0: millis() = 18651
ITimer0: millis() = 19651
ITimer0: millis() = 20651
ITimer1: millis() = 20676
ITimer0: millis() = 21651
ITimer0: millis() = 22651

4. ISR_16_Timers_Array_Complex on ESP32C3_DEV

The following is the sample terminal output when running example ISR_16_Timers_Array_Complex on ESP32C3_DEV to demonstrate of ISR Hardware Timer, especially when system is very busy or blocked. The 16 independent ISR timers are programmed to be activated repetitively after certain intervals, is activated exactly after that programmed interval !!!

Starting ISR_16_Timers_Array_Complex on ESP32C3_DEV
ESP32_New_TimerInterrupt v1.5.0
CPU Frequency = 160 MHz
Starting ITimer OK, millis() = 2187
SimpleTimer : 2, ms : 12193, Dms : 10004
Timer : 0, programmed : 5000, actual : 5008
Timer : 1, programmed : 10000, actual : 0
Timer : 2, programmed : 15000, actual : 0
Timer : 3, programmed : 20000, actual : 0
Timer : 4, programmed : 25000, actual : 0
Timer : 5, programmed : 30000, actual : 0
Timer : 6, programmed : 35000, actual : 0
Timer : 7, programmed : 40000, actual : 0
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 22251, Dms : 10058
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15008
Timer : 3, programmed : 20000, actual : 20008
Timer : 4, programmed : 25000, actual : 0
Timer : 5, programmed : 30000, actual : 0
Timer : 6, programmed : 35000, actual : 0
Timer : 7, programmed : 40000, actual : 0
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 32310, Dms : 10059
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20008
Timer : 4, programmed : 25000, actual : 25008
Timer : 5, programmed : 30000, actual : 30008
Timer : 6, programmed : 35000, actual : 0
Timer : 7, programmed : 40000, actual : 0
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 42369, Dms : 10059
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25008
Timer : 5, programmed : 30000, actual : 30008
Timer : 6, programmed : 35000, actual : 35008
Timer : 7, programmed : 40000, actual : 40008
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 52429, Dms : 10060
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30008
Timer : 6, programmed : 35000, actual : 35008
Timer : 7, programmed : 40000, actual : 40008
Timer : 8, programmed : 45000, actual : 45008
Timer : 9, programmed : 50000, actual : 50008
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 62490, Dms : 10061
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30000
Timer : 6, programmed : 35000, actual : 35008
Timer : 7, programmed : 40000, actual : 40008
Timer : 8, programmed : 45000, actual : 45008
Timer : 9, programmed : 50000, actual : 50008
Timer : 10, programmed : 55000, actual : 55008
Timer : 11, programmed : 60000, actual : 60008
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 72551, Dms : 10061
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30000
Timer : 6, programmed : 35000, actual : 35000
Timer : 7, programmed : 40000, actual : 40008
Timer : 8, programmed : 45000, actual : 45008
Timer : 9, programmed : 50000, actual : 50008
Timer : 10, programmed : 55000, actual : 55008
Timer : 11, programmed : 60000, actual : 60008
Timer : 12, programmed : 65000, actual : 65008
Timer : 13, programmed : 70000, actual : 70008
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 82613, Dms : 10062
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30000
Timer : 6, programmed : 35000, actual : 35000
Timer : 7, programmed : 40000, actual : 40000
Timer : 8, programmed : 45000, actual : 45008
Timer : 9, programmed : 50000, actual : 50008
Timer : 10, programmed : 55000, actual : 55008
Timer : 11, programmed : 60000, actual : 60008
Timer : 12, programmed : 65000, actual : 65008
Timer : 13, programmed : 70000, actual : 70008
Timer : 14, programmed : 75000, actual : 75008
Timer : 15, programmed : 80000, actual : 80008

5. ISR_16_Timers_Array on ESP32S2_DEV

The following is the sample terminal output when running example ISR_16_Timers_Array on ESP32S2_DEV to demonstrate of ISR Hardware Timer, especially when system is very busy or blocked. The 16 independent ISR timers are programmed to be activated repetitively after certain intervals, is activated exactly after that programmed interval !!!

Starting ISR_16_Timers_Array on ESP32S2_DEV
ESP32_New_TimerInterrupt v1.5.0
CPU Frequency = 240 MHz
Starting ITimer OK, millis() = 2538
simpleTimerDoingSomething2s: Delta programmed ms = 2000, actual = 10008
simpleTimerDoingSomething2s: Delta programmed ms = 2000, actual = 10005

6. ISR_16_Timers_Array_Complex on ESP32S3_DEV

The following is the sample terminal output when running example ISR_16_Timers_Array_Complex on ESP32S3_DEV to demonstrate of ISR Hardware Timer, especially when system is very busy or blocked. The 16 independent ISR timers are programmed to be activated repetitively after certain intervals, is activated exactly after that programmed interval !!!

Starting ISR_16_Timers_Array_Complex on ESP32S3_DEV
ESP32_New_TimerInterrupt v1.5.0
CPU Frequency = 240 MHz
[TISR] ESP32_S3_TimerInterrupt: _timerNo = 1 , _fre = 1000000
[TISR] TIMER_BASE_CLK = 80000000 , TIMER_DIVIDER = 80
[TISR] _timerIndex = 1 , _timerGroup = 0
[TISR] _count = 0 - 10000
[TISR] timer_set_alarm_value = 10000.00
Starting ITimer OK, millis() = 2118
SimpleTimer : 2, ms : 12117, Dms : 9999
Timer : 0, programmed : 5000, actual : 5009
Timer : 1, programmed : 10000, actual : 0
Timer : 2, programmed : 15000, actual : 0
Timer : 3, programmed : 20000, actual : 0
Timer : 4, programmed : 25000, actual : 0
Timer : 5, programmed : 30000, actual : 0
Timer : 6, programmed : 35000, actual : 0
Timer : 7, programmed : 40000, actual : 0
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 22180, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15009
Timer : 3, programmed : 20000, actual : 20009
Timer : 4, programmed : 25000, actual : 0
Timer : 5, programmed : 30000, actual : 0
Timer : 6, programmed : 35000, actual : 0
Timer : 7, programmed : 40000, actual : 0
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 32243, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20009
Timer : 4, programmed : 25000, actual : 25009
Timer : 5, programmed : 30000, actual : 30009
Timer : 6, programmed : 35000, actual : 0
Timer : 7, programmed : 40000, actual : 0
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 42306, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25009
Timer : 5, programmed : 30000, actual : 30009
Timer : 6, programmed : 35000, actual : 35009
Timer : 7, programmed : 40000, actual : 40009
Timer : 8, programmed : 45000, actual : 0
Timer : 9, programmed : 50000, actual : 0
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 52369, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30009
Timer : 6, programmed : 35000, actual : 35009
Timer : 7, programmed : 40000, actual : 40009
Timer : 8, programmed : 45000, actual : 45009
Timer : 9, programmed : 50000, actual : 50009
Timer : 10, programmed : 55000, actual : 0
Timer : 11, programmed : 60000, actual : 0
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 62432, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30000
Timer : 6, programmed : 35000, actual : 35009
Timer : 7, programmed : 40000, actual : 40009
Timer : 8, programmed : 45000, actual : 45009
Timer : 9, programmed : 50000, actual : 50009
Timer : 10, programmed : 55000, actual : 55009
Timer : 11, programmed : 60000, actual : 60009
Timer : 12, programmed : 65000, actual : 0
Timer : 13, programmed : 70000, actual : 0
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 72495, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30000
Timer : 6, programmed : 35000, actual : 35000
Timer : 7, programmed : 40000, actual : 40009
Timer : 8, programmed : 45000, actual : 45009
Timer : 9, programmed : 50000, actual : 50009
Timer : 10, programmed : 55000, actual : 55009
Timer : 11, programmed : 60000, actual : 60009
Timer : 12, programmed : 65000, actual : 65009
Timer : 13, programmed : 70000, actual : 70009
Timer : 14, programmed : 75000, actual : 0
Timer : 15, programmed : 80000, actual : 0
SimpleTimer : 2, ms : 82558, Dms : 10063
Timer : 0, programmed : 5000, actual : 5000
Timer : 1, programmed : 10000, actual : 10000
Timer : 2, programmed : 15000, actual : 15000
Timer : 3, programmed : 20000, actual : 20000
Timer : 4, programmed : 25000, actual : 25000
Timer : 5, programmed : 30000, actual : 30000
Timer : 6, programmed : 35000, actual : 35000
Timer : 7, programmed : 40000, actual : 40000
Timer : 8, programmed : 45000, actual : 45009
Timer : 9, programmed : 50000, actual : 50009
Timer : 10, programmed : 55000, actual : 55009
Timer : 11, programmed : 60000, actual : 60009
Timer : 12, programmed : 65000, actual : 65009
Timer : 13, programmed : 70000, actual : 70009
Timer : 14, programmed : 75000, actual : 75009
Timer : 15, programmed : 80000, actual : 80009

Debug

Debug is enabled by default on Serial.

You can also change the debugging level (TIMERINTERRUPT_LOGLEVEL) from 0 to 4

// These define's must be placed at the beginning before #include "ESP32_New_TimerInterrupt.h"
// _TIMERINTERRUPT_LOGLEVEL_ from 0 to 4
// Don't define _TIMERINTERRUPT_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system.
#define TIMER_INTERRUPT_DEBUG         0
#define _TIMERINTERRUPT_LOGLEVEL_     0

Troubleshooting

If you get compilation errors, more often than not, you may need to install a newer version of the core for Arduino boards.

Sometimes, the library will only work if you update the board core to the latest version because I am using newly added functions.

Issues

Submit issues to: ESP32_New_TimerInterrupt issues

TO DO

Search for bug and improvement.

DONE

Basic hardware timers for ESP32, ESP32-S2, ESP32-S3 and ESP32_C3 for ESP32 core v2.0.0-rc1+
More hardware-initiated software-enabled timers
Longer time interval
Similar features for remaining Arduino boards such as SAMD21, SAMD51, SAM-DUE, nRF52, ESP8266, STM32, etc.
Fix compiler errors due to conflict to some libraries.
Add complex examples.
Avoid using D1 in examples due to issue with core v2.0.0 and v2.0.1.
Avoid using float in ISR due to issue with core v2.0.0 and v2.0.1.
Fix multiple-definitions linker error. Drop src_cpp and src_h directories
Optimize library code by using reference-passing instead of value-passing
Add support to ESP32-S3 (ESP32S3_DEV, ESP32_S3_BOX, UM TINYS3, UM PROS3, UM FEATHERS3, etc.)
Add support to many more boards, such as

ESP32_S2 : ESP32S2 Native USB, UM FeatherS2 Neo, UM TinyS2, UM RMP, microS2, LOLIN_S2_MINI, LOLIN_S2_PICO, ADAFRUIT_FEATHER_ESP32S2, ADAFRUIT_FEATHER_ESP32S2_TFT, ATMegaZero ESP32-S2, Deneyap Mini, FRANZININHO_WIFI, FRANZININHO_WIFI_MSC
ESP32_S3 : UM TinyS3, UM PROS3, UM FeatherS3, ESP32_S3_USB_OTG, ESP32S3_CAM_LCD, DFROBOT_FIREBEETLE_2_ESP32S3, ADAFRUIT_FEATHER_ESP32S3_TFT
ESP32_C3 : LOLIN_C3_MINI, DFROBOT_BEETLE_ESP32_C3, ADAFRUIT_QTPY_ESP32C3, AirM2M_CORE_ESP32C3, XIAO_ESP32C3

Use allman astyle and add utils

Contributions and Thanks

Many thanks for everyone for bug reporting, new feature suggesting, testing and contributing to the development of this library.

Contributing

If you want to contribute to this project:

Report bugs and errors
Ask for enhancements
Create issues and pull requests
Tell other people about this library

License

The library is licensed under MIT

Name		Name	Last commit message	Last commit date
Latest commit History 62 Commits
.github		.github
examples		examples
platformio		platformio
src		src
utils		utils
.codespellrc		.codespellrc
.gitignore		.gitignore
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md
changelog.md		changelog.md
keywords.txt		keywords.txt
library.json		library.json
library.properties		library.properties

	#if !defined( ESP32 )
	#error This code is intended to run on the ESP32 platform! Please check your Tools->Board setting.
	#endif

	// These define's must be placed at the beginning before #include "ESP32_New_TimerInterrupt.h"
	#define _TIMERINTERRUPT_LOGLEVEL_ 4

	#include "ESP32_New_TimerInterrupt.h"
	#include "ESP32_New_ISR_Timer.h"

	#include <SimpleTimer.h> // https://github.com/jfturcot/SimpleTimer

	// Don't use PIN_D1 in core v2.0.0 and v2.0.1. Check https://github.com/espressif/arduino-esp32/issues/5868

	#ifndef LED_BLUE
	#define LED_BLUE 25
	#endif

	#ifndef LED_RED
	#define LED_RED 27
	#endif

	// Don't use PIN_D1 in core v2.0.0 and v2.0.1. Check https://github.com/espressif/arduino-esp32/issues/5868
	// Don't use PIN_D2 with ESP32_C3 (crash)
	#define PIN_D19 19 // Pin D19 mapped to pin GPIO9 of ESP32

	#define HW_TIMER_INTERVAL_US 10000L

	volatile uint32_t startMillis = 0;

	// Init ESP32 timer 1
	ESP32Timer ITimer(1);

	// Init ESP32_ISR_Timer
	ESP32_ISR_Timer ISR_Timer;

	#define LED_TOGGLE_INTERVAL_MS 2000L

	// With core v2.0.0+, you can't use Serial.print/println in ISR or crash.
	// and you can't use float calculation inside ISR
	// Only OK in core v1.0.6-
	bool IRAM_ATTR TimerHandler(void * timerNo)
	{
	static bool toggle = false;
	static int timeRun = 0;

	ISR_Timer.run();

	// Toggle LED every LED_TOGGLE_INTERVAL_MS = 2000ms = 2s
	if (++timeRun == ((LED_TOGGLE_INTERVAL_MS * 1000) / HW_TIMER_INTERVAL_US) )
	{
	timeRun = 0;

	//timer interrupt toggles pin PIN_D19
	digitalWrite(PIN_D19, toggle);
	toggle = !toggle;
	}

	return true;
	}

	/////////////////////////////////////////////////

	#define NUMBER_ISR_TIMERS 16

	typedef void (*irqCallback) ();

	/////////////////////////////////////////////////

	#define USE_COMPLEX_STRUCT true

	#if USE_COMPLEX_STRUCT

	typedef struct
	{
	irqCallback irqCallbackFunc;
	uint32_t TimerInterval;
	unsigned long deltaMillis;
	unsigned long previousMillis;
	} ISRTimerData;

	// In NRF52, avoid doing something fancy in ISR, for example Serial.print()
	// The pure simple Serial.prints here are just for demonstration and testing. Must be eliminate in working environment
	// Or you can get this run-time error / crash

	void doingSomething(int index);

	#else

	volatile unsigned long deltaMillis [NUMBER_ISR_TIMERS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
	volatile unsigned long previousMillis [NUMBER_ISR_TIMERS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

	// You can assign any interval for any timer here, in milliseconds
	uint32_t TimerInterval[NUMBER_ISR_TIMERS] =
	{
	5000L, 10000L, 15000L, 20000L, 25000L, 30000L, 35000L, 40000L,
	45000L, 50000L, 55000L, 60000L, 65000L, 70000L, 75000L, 80000L
	};

	void doingSomething(int index)
	{
	unsigned long currentMillis = millis();

	deltaMillis[index] = currentMillis - previousMillis[index];
	previousMillis[index] = currentMillis;
	}

	#endif

	////////////////////////////////////
	// Shared
	////////////////////////////////////

	void doingSomething0()
	{
	doingSomething(0);
	}

	void doingSomething1()
	{
	doingSomething(1);
	}

	void doingSomething2()
	{
	doingSomething(2);
	}

	void doingSomething3()
	{
	doingSomething(3);
	}

	void doingSomething4()
	{
	doingSomething(4);
	}

	void doingSomething5()
	{
	doingSomething(5);
	}

	void doingSomething6()
	{
	doingSomething(6);
	}

	void doingSomething7()
	{
	doingSomething(7);
	}

	void doingSomething8()
	{
	doingSomething(8);
	}

	void doingSomething9()
	{
	doingSomething(9);
	}

	void doingSomething10()
	{
	doingSomething(10);
	}

	void doingSomething11()
	{
	doingSomething(11);
	}

	void doingSomething12()
	{
	doingSomething(12);
	}

	void doingSomething13()
	{
	doingSomething(13);
	}

	void doingSomething14()
	{
	doingSomething(14);
	}

	void doingSomething15()
	{
	doingSomething(15);
	}

	#if USE_COMPLEX_STRUCT

	ISRTimerData curISRTimerData[NUMBER_ISR_TIMERS] =
	{
	//irqCallbackFunc, TimerInterval, deltaMillis, previousMillis
	{ doingSomething0, 5000L, 0, 0 },
	{ doingSomething1, 10000L, 0, 0 },
	{ doingSomething2, 15000L, 0, 0 },
	{ doingSomething3, 20000L, 0, 0 },
	{ doingSomething4, 25000L, 0, 0 },
	{ doingSomething5, 30000L, 0, 0 },
	{ doingSomething6, 35000L, 0, 0 },
	{ doingSomething7, 40000L, 0, 0 },
	{ doingSomething8, 45000L, 0, 0 },
	{ doingSomething9, 50000L, 0, 0 },
	{ doingSomething10, 55000L, 0, 0 },
	{ doingSomething11, 60000L, 0, 0 },
	{ doingSomething12, 65000L, 0, 0 },
	{ doingSomething13, 70000L, 0, 0 },
	{ doingSomething14, 75000L, 0, 0 },
	{ doingSomething15, 80000L, 0, 0 }
	};

	void doingSomething(int index)
	{
	unsigned long currentMillis = millis();

	curISRTimerData[index].deltaMillis = currentMillis - curISRTimerData[index].previousMillis;
	curISRTimerData[index].previousMillis = currentMillis;
	}

	#else

	irqCallback irqCallbackFunc[NUMBER_ISR_TIMERS] =
	{
	doingSomething0, doingSomething1, doingSomething2, doingSomething3,
	doingSomething4, doingSomething5, doingSomething6, doingSomething7,
	doingSomething8, doingSomething9, doingSomething10, doingSomething11,
	doingSomething12, doingSomething13, doingSomething14, doingSomething15
	};

	#endif
	///////////////////////////////////////////

	#define SIMPLE_TIMER_MS 2000L

	// Init SimpleTimer
	SimpleTimer simpleTimer;

	// Here is software Timer, you can do somewhat fancy stuffs without many issues.
	// But always avoid
	// 1. Long delay() it just doing nothing and pain-without-gain wasting CPU power.Plan and design your code / strategy ahead
	// 2. Very long "do", "while", "for" loops without predetermined exit time.
	void simpleTimerDoingSomething2s()
	{
	static unsigned long previousMillis = startMillis;

	unsigned long currMillis = millis();

	Serial.print(F("SimpleTimer : "));
	Serial.print(SIMPLE_TIMER_MS / 1000);
	Serial.print(F(", ms : "));
	Serial.print(currMillis);
	Serial.print(F(", Dms : "));
	Serial.println(currMillis - previousMillis);

	for (uint16_t i = 0; i < NUMBER_ISR_TIMERS; i++)
	{
	#if USE_COMPLEX_STRUCT
	Serial.print(F("Timer : "));
	Serial.print(i);
	Serial.print(F(", programmed : "));
	Serial.print(curISRTimerData[i].TimerInterval);
	Serial.print(F(", actual : "));
	Serial.println(curISRTimerData[i].deltaMillis);
	#else
	Serial.print(F("Timer : "));
	Serial.print(i);
	Serial.print(F(", programmed : "));
	Serial.print(TimerInterval[i]);
	Serial.print(F(", actual : "));
	Serial.println(deltaMillis[i]);
	#endif
	}

	previousMillis = currMillis;
	}

	void setup()
	{
	pinMode(PIN_D19, OUTPUT);

	Serial.begin(115200);

	while (!Serial && millis() < 5000);

	delay(500);

	Serial.print(F("\nStarting ISR_16_Timers_Array_Complex on "));
	Serial.println(ARDUINO_BOARD);
	Serial.println(ESP32_NEW_TIMERINTERRUPT_VERSION);
	Serial.print(F("CPU Frequency = "));
	Serial.print(F_CPU / 1000000);
	Serial.println(F(" MHz"));

	// Interval in microsecs
	if (ITimer.attachInterruptInterval(HW_TIMER_INTERVAL_US, TimerHandler))
	{
	startMillis = millis();
	Serial.print(F("Starting ITimer OK, millis() = "));
	Serial.println(startMillis);
	}
	else
	Serial.println(F("Can't set ITimer. Select another freq. or timer"));

	startMillis = millis();

	// Just to demonstrate, don't use too many ISR Timers if not absolutely necessary
	// You can use up to 16 timer for each ISR_Timer
	for (uint16_t i = 0; i < NUMBER_ISR_TIMERS; i++)
	{
	#if USE_COMPLEX_STRUCT
	curISRTimerData[i].previousMillis = startMillis;
	ISR_Timer.setInterval(curISRTimerData[i].TimerInterval, curISRTimerData[i].irqCallbackFunc);
	#else
	previousMillis[i] = millis();
	ISR_Timer.setInterval(TimerInterval[i], irqCallbackFunc[i]);
	#endif
	}

	// You need this timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary.
	simpleTimer.setInterval(SIMPLE_TIMER_MS, simpleTimerDoingSomething2s);
	}

	#define BLOCKING_TIME_MS 10000L

	void loop()
	{
	// This unadvised blocking task is used to demonstrate the blocking effects onto the execution and accuracy to Software timer
	// You see the time elapse of ISR_Timer still accurate, whereas very unaccurate for Software Timer
	// The time elapse for 2000ms software timer now becomes 3000ms (BLOCKING_TIME_MS)
	// While that of ISR_Timer is still prefect.
	delay(BLOCKING_TIME_MS);

	// You need this Software timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary
	// You don't need to and never call ISR_Timer.run() here in the loop(). It's already handled by ISR timer.
	simpleTimer.run();
	}

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khoih-prog/ESP32_New_TimerInterrupt

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ESP32_New_TimerInterrupt Library

Table of Contents

Why do we need this ESP32_New_TimerInterrupt library

Important Notes

Features

Why using ISR-based Hardware Timer Interrupt is better

Currently supported Boards

Important Notes about ISR

Prerequisites

Installation

Use Arduino Library Manager

Manual Install

VS Code & PlatformIO

HOWTO Fix Multiple Definitions Linker Error

HOWTO Use analogRead() with ESP32 running WiFi and/or BlueTooth (BT/BLE)

1. ESP32 has 2 ADCs, named ADC1 and ADC2

2. ESP32 ADCs functions

3.. ESP32 WiFi uses ADC2 for WiFi functions

More useful Information

How to use

Examples:

Example ISR_16_Timers_Array_Complex

Debug Terminal Output Samples

1. TimerInterruptTest on ESP32C3_DEV

2. Change_Interval on ESP32_DEV

3. Argument_None on ESP32S2_DEV

4. ISR_16_Timers_Array_Complex on ESP32C3_DEV

5. ISR_16_Timers_Array on ESP32S2_DEV

6. ISR_16_Timers_Array_Complex on ESP32S3_DEV

Debug

Troubleshooting

Issues

TO DO

DONE

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Contributing

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HOWTO Fix `Multiple Definitions` Linker Error

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