ESP8266_PWM Library

Important Change from v1.2.0
Why do we need this ESP8266_PWM library
Changelog
Prerequisites
Installation
HOWTO Fix Multiple Definitions Linker Error
More useful Information
Examples
Example ISR_16_PWMs_Array_Complex
Debug Terminal Output Samples
Debug
Troubleshooting
Issues
TO DO
DONE
Contributions and Thanks
Contributing
License
Copyright

Important Change from v1.2.0

Please have a look at HOWTO Fix Multiple Definitions Linker Error

As more complex calculation and check inside ISR are introduced from v1.2.0, there is possibly some crash depending on use-case.

You can modify to use larger HW_TIMER_INTERVAL_US, (from current 20uS), according to your board and use-case if crash happens.

// Current 20uS
#define HW_TIMER_INTERVAL_US      20L

Why do we need this ESP8266_PWM library

Features

This library enables you to use Interrupt from Hardware Timers on an ESP8266-based board to create and output PWM to pins. The maximum PWM frequency is currently limited at 500Hz. Now you can also modify PWM settings on-the-fly.

This library enables you to use Interrupt from Hardware Timers on an ESP8266-based board to create and output PWM to pins. It now supports 16 ISR-based synchronized PWM channels, while consuming only 1 Hardware Timer. PWM interval can be very long (uint32_t millisecs). The most important feature is they're ISR-based PWM channels. Therefore, their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. These hardware PWM channels, 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.

As Hardware Timers are rare, and very precious assets of any board, this library now enables you to use up to 16 ISR-based synchronized PWM channels, 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 PWM channels. Therefore, their executions are not blocked by bad-behaving functions / tasks. This important feature is absolutely necessary for mission-critical tasks.

The ISR_16_PWMs_Array_Complex example will demonstrate the nearly perfect accuracy compared to software timers by printing the actual elapsed millisecs of each type of PWM channels.

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.

Why using ISR-based PWM-channels 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 PWM-channels 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

ESP8266 boards, such as ESP8266_NODEMCU_ESP12E, etc.

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.
ESP8266 Core 3.0.2+ for ESP8266-based boards.
SimpleTimer library to use with some examples.

Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for ESP8266_PWM, 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 ESP8266_PWM page.
Download the latest release ESP8266_PWM-main.zip.
Extract the zip file to ESP8266_PWM-main directory
Copy whole ESP8266_PWM-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO

Install VS Code
Install PlatformIO
Install ESP8266_PWM library by using Library Manager. Search for ESP8266_PWM 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 include this .hpp file

// Can be included as many times as necessary, without `Multiple Definitions` Linker Error
#include "ESP8266_PWM.hpp"     //https://github.com/khoih-prog/ESP8266_PWM

in many files. But be sure to use the following .h file 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 "ESP8266_PWM.h"           //https://github.com/khoih-prog/ESP8266_PWM

Check the new multiFileProject example for a HOWTO demo.

Have a look at the discussion in Different behaviour using the src_cpp or src_h lib #80

More useful Information

The ESP8266 timers are badly designed, using only 23-bit counter along with maximum 256 prescaler. They're only better than UNO / Mega. The ESP8266 has two hardware timers, but timer0 has been used for WiFi and it's not advisable to use. Only timer1 is available. The timer1's 23-bit counter terribly can count only up to 8,388,607. So the timer1 maximum interval is very short. Using 256 prescaler, maximum timer1 interval is only 26.843542 seconds !!!

The timer1 counters can be configured to support automatic reload.

Now with these new 16 ISR-based timers, 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

Examples:

ISR_16_PWMs_Array
ISR_16_PWMs_Array_Complex
ISR_16_PWMs_Array_Simple
ISR_Changing_PWM
ISR_Modify_PWM
multiFileProject New

Example ISR_16_PWMs_Array_Complex

ESP8266_PWM/examples/ISR_16_PWMs_Array_Complex/ISR_16_PWMs_Array_Complex.ino

Lines 24 to 481 in 192da87

    
           #if !defined(ESP8266) 
        
             #error This code is designed to run on ESP8266 and ESP8266-based boards! Please check your Tools->Board setting. 
        
           #endif 
        
           // These define's must be placed at the beginning before #include "ESP8266_PWM.h" 
        
           // _PWM_LOGLEVEL_ from 0 to 4 
        
           // Don't define _PWM_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system. 
        
           #define _PWM_LOGLEVEL_      4 
        
           #define USING_MICROS_RESOLUTION       true    //false 
        
           // Default is true, uncomment to false 
        
           //#define CHANGING_PWM_END_OF_CYCLE     false 
        
           // Select a Timer Clock 
        
           #define USING_TIM_DIV1                true              // for shortest and most accurate timer 
        
           #define USING_TIM_DIV16               false             // for medium time and medium accurate timer 
        
           #define USING_TIM_DIV256              false             // for longest timer but least accurate. Default 
        
           // To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error 
        
           #include "ESP8266_PWM.h" 
        
           #include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer 
        
           #ifndef LED_BUILTIN 
        
             #define LED_BUILTIN       2 
        
           #endif 
        
           #define HW_TIMER_INTERVAL_US      20L 
        
           volatile uint32_t startMicros = 0; 
        
           // Init ESP8266Timer 
        
           ESP8266Timer ITimer; 
        
           // Init ESP8266_ISR_PWM 
        
           ESP8266_PWM ISR_PWM; 
        
           void IRAM_ATTR TimerHandler() 
        
           { 
        
             ISR_PWM.run(); 
        
           } 
        
           ///////////////////////////////////////////////// 
        
           #define NUMBER_ISR_PWMS         8 
        
           //PIN_D0 can't be used for PWM/I2C 
        
           #define PIN_D0            16        // Pin D0 mapped to pin GPIO16/USER/WAKE of ESP8266. This pin is also used for Onboard-Blue LED. PIN_D0 = 0 => LED ON 
        
           #define PIN_D1            5         // Pin D1 mapped to pin GPIO5 of ESP8266 
        
           #define PIN_D2            4         // Pin D2 mapped to pin GPIO4 of ESP8266 
        
           #define PIN_D3            0         // Pin D3 mapped to pin GPIO0/FLASH of ESP8266 
        
           #define PIN_D4            2         // Pin D4 mapped to pin GPIO2/TXD1 of ESP8266 
        
           //#define PIN_LED           2         // Pin D4 mapped to pin GPIO2/TXD1 of ESP8266, NodeMCU and WeMoS, control on-board LED 
        
           #define PIN_D5            14        // Pin D5 mapped to pin GPIO14/HSCLK of ESP8266 
        
           #define PIN_D6            12        // Pin D6 mapped to pin GPIO12/HMISO of ESP8266 
        
           #define PIN_D7            13        // Pin D7 mapped to pin GPIO13/RXD2/HMOSI of ESP8266 
        
           #define PIN_D8            15        // Pin D8 mapped to pin GPIO15/TXD2/HCS of ESP8266 
        
           #define PIN_D9            3         // Pin D9 /RX mapped to pin GPIO3/RXD0 of ESP8266 
        
           #define PIN_D10           1         // Pin D10/TX mapped to pin GPIO1/TXD0 of ESP8266 
        
           //Don't use pins GPIO6 to GPIO11 as already connected to flash, etc. Use them can crash the program 
        
           //GPIO9(D11/SD2) and GPIO11 can be used only if flash in DIO mode ( not the default QIO mode) 
        
           #define PIN_D11           9         // Pin D11/SD2 mapped to pin GPIO9/SDD2 of ESP8266 
        
           #define PIN_D12           10        // Pin D12/SD3 mapped to pin GPIO10/SDD3 of ESP8266 
        
           typedef void (*irqCallback)  (); 
        
           ////////////////////////////////////////////////////// 
        
           #define USE_COMPLEX_STRUCT      true 
        
           #define USING_PWM_FREQUENCY     true 
        
           ////////////////////////////////////////////////////// 
        
           #if USE_COMPLEX_STRUCT 
        
           typedef struct 
        
           { 
        
             uint32_t      PWM_Pin; 
        
             irqCallback   irqCallbackStartFunc; 
        
             irqCallback   irqCallbackStopFunc; 
        
           #if USING_PWM_FREQUENCY   
        
             float         PWM_Freq; 
        
           #else   
        
             uint32_t      PWM_Period; 
        
           #endif 
        
             float         PWM_DutyCycle; 
        
             uint64_t      deltaMicrosStart; 
        
             uint64_t      previousMicrosStart; 
        
             uint64_t      deltaMicrosStop; 
        
             uint64_t      previousMicrosStop; 
        
           } ISR_PWM_Data; 
        
           // 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 doingSomethingStart(int index); 
        
           void doingSomethingStop(int index); 
        
           #else   // #if USE_COMPLEX_STRUCT 
        
           volatile unsigned long deltaMicrosStart    [] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 
        
           volatile unsigned long previousMicrosStart [] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 
        
           volatile unsigned long deltaMicrosStop     [] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 
        
           volatile unsigned long previousMicrosStop  [] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 
        
           // You can assign pins here. Be carefull to select good pin to use or crash 
        
           uint32_t PWM_Pin[] = 
        
           { 
        
              PIN_D0, PIN_D1, LED_BUILTIN, PIN_D3, PIN_D4, PIN_D5, PIN_D6, PIN_D7 
        
           }; 
        
           // You can assign any interval for any timer here, in microseconds 
        
           uint32_t PWM_Period[] = 
        
           { 
        
             1000000,   500000,   333333,   250000,   200000,   166667,   142857,   125000 
        
           }; 
        
           // You can assign any interval for any timer here, in Hz 
        
           float PWM_Freq[] = 
        
           { 
        
             1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  7.0,  8.0 
        
           }; 
        
           // You can assign any interval for any timer here, in Microseconds 
        
           float PWM_DutyCycle[] = 
        
           { 
        
              5.0, 10.0, 20.0, 30.0, 40.0, 45.0, 50.0, 55.0 
        
           }; 
        
           /////////////////////////////////// 
        
           void doingSomethingStart(int index) 
        
           { 
        
             unsigned long currentMicros  = micros(); 
        
             deltaMicrosStart[index]    = currentMicros - previousMicrosStart[index]; 
        
             previousMicrosStart[index] = currentMicros; 
        
           } 
        
           void doingSomethingStop(int index) 
        
           { 
        
             unsigned long currentMicros  = micros(); 
        
             //deltaMicrosStop[index]    = currentMicros - previousMicrosStop[index]; 
        
             // Count from start to stop PWM pulse 
        
             deltaMicrosStop[index]    = currentMicros - previousMicrosStart[index]; 
        
             previousMicrosStop[index] = currentMicros; 
        
           } 
        
           #endif    // #if USE_COMPLEX_STRUCT 
        
           //////////////////////////////////// 
        
           // Shared 
        
           //////////////////////////////////// 
        
           void doingSomethingStart0() 
        
           { 
        
             doingSomethingStart(0); 
        
           } 
        
           void doingSomethingStart1() 
        
           { 
        
             doingSomethingStart(1); 
        
           } 
        
           void doingSomethingStart2() 
        
           { 
        
             doingSomethingStart(2); 
        
           } 
        
           void doingSomethingStart3() 
        
           { 
        
             doingSomethingStart(3); 
        
           } 
        
           void doingSomethingStart4() 
        
           { 
        
             doingSomethingStart(4); 
        
           } 
        
           void doingSomethingStart5() 
        
           { 
        
             doingSomethingStart(5); 
        
           } 
        
           void doingSomethingStart6() 
        
           { 
        
             doingSomethingStart(6); 
        
           } 
        
           void doingSomethingStart7() 
        
           { 
        
             doingSomethingStart(7); 
        
           } 
        
           ////////////////////////////////////////////////////// 
        
           void doingSomethingStop0() 
        
           { 
        
             doingSomethingStop(0); 
        
           } 
        
           void doingSomethingStop1() 
        
           { 
        
             doingSomethingStop(1); 
        
           } 
        
           void doingSomethingStop2() 
        
           { 
        
             doingSomethingStop(2); 
        
           } 
        
           void doingSomethingStop3() 
        
           { 
        
             doingSomethingStop(3); 
        
           } 
        
           void doingSomethingStop4() 
        
           { 
        
             doingSomethingStop(4); 
        
           } 
        
           void doingSomethingStop5() 
        
           { 
        
             doingSomethingStop(5); 
        
           } 
        
           void doingSomethingStop6() 
        
           { 
        
             doingSomethingStop(6); 
        
           } 
        
           void doingSomethingStop7() 
        
           { 
        
             doingSomethingStop(7); 
        
           } 
        
           ////////////////////////////////////////////////////// 
        
           #if USE_COMPLEX_STRUCT 
        
             #if USING_PWM_FREQUENCY 
        
             ISR_PWM_Data curISR_PWM_Data[] = 
        
             { 
        
               //pin, irqCallbackStartFunc, irqCallbackStopFunc, PWM_Freq, PWM_DC, deltaMicrosStart, previousMicrosStart, deltaMicrosStop, previousMicrosStop 
        
               { PIN_D0,       doingSomethingStart0,   doingSomethingStop0,   1.0,   5.0, 0, 0, 0, 0 }, 
        
               { PIN_D1,       doingSomethingStart1,   doingSomethingStop1,   2.0,  10.0, 0, 0, 0, 0 }, 
        
               { LED_BUILTIN,  doingSomethingStart2,   doingSomethingStop2,   3.0,  20.0, 0, 0, 0, 0 }, 
        
               { PIN_D3,       doingSomethingStart3,   doingSomethingStop3,   4.0,  30.0, 0, 0, 0, 0 }, 
        
               { PIN_D4,       doingSomethingStart4,   doingSomethingStop4,   5.0,  40.0, 0, 0, 0, 0 }, 
        
               { PIN_D5,       doingSomethingStart5,   doingSomethingStop5,   6.0,  45.0, 0, 0, 0, 0 }, 
        
               { PIN_D6,       doingSomethingStart6,   doingSomethingStop6,   7.0,  50.0, 0, 0, 0, 0 }, 
        
               { PIN_D7,       doingSomethingStart7,   doingSomethingStop7,   8.0,  55.0, 0, 0, 0, 0 }, 
        
             }; 
        
             #else   // #if USING_PWM_FREQUENCY 
        
             ISR_PWM_Data curISR_PWM_Data[] = 
        
             { 
        
               //pin, irqCallbackStartFunc, irqCallbackStopFunc, PWM_Period, PWM_DC, deltaMicrosStart, previousMicrosStart, deltaMicrosStop, previousMicrosStop 
        
               { PIN_D0,       doingSomethingStart0,   doingSomethingStop0,   1000000,   5.0, 0, 0, 0, 0 }, 
        
               { PIN_D1,       doingSomethingStart1,   doingSomethingStop1,    500000,  10.0, 0, 0, 0, 0 }, 
        
               { LED_BUILTIN,  doingSomethingStart2,   doingSomethingStop2,    333333,  20.0, 0, 0, 0, 0 }, 
        
               { PIN_D3,       doingSomethingStart3,   doingSomethingStop3,    250000,  30.0, 0, 0, 0, 0 }, 
        
               { PIN_D4,       doingSomethingStart4,   doingSomethingStop4,    200000,  40.0, 0, 0, 0, 0 }, 
        
               { PIN_D5,       doingSomethingStart5,   doingSomethingStop5,    166667,  45.0, 0, 0, 0, 0 }, 
        
               { PIN_D6,       doingSomethingStart6,   doingSomethingStop6,    142857,  50.0, 0, 0, 0, 0 }, 
        
               { PIN_D7,       doingSomethingStart7,   doingSomethingStop7,    125000   55.0, 0, 0, 0, 0 }, 
        
             }; 
        
             #endif  // #if USING_PWM_FREQUENCY 
        
           void doingSomethingStart(int index) 
        
           { 
        
             unsigned long currentMicros  = micros(); 
        
             curISR_PWM_Data[index].deltaMicrosStart    = currentMicros - curISR_PWM_Data[index].previousMicrosStart; 
        
             curISR_PWM_Data[index].previousMicrosStart = currentMicros; 
        
           } 
        
           void doingSomethingStop(int index) 
        
           { 
        
             unsigned long currentMicros  = micros(); 
        
             //curISR_PWM_Data[index].deltaMicrosStop     = currentMicros - curISR_PWM_Data[index].previousMicrosStop; 
        
             // Count from start to stop PWM pulse 
        
             curISR_PWM_Data[index].deltaMicrosStop     = currentMicros - curISR_PWM_Data[index].previousMicrosStart; 
        
             curISR_PWM_Data[index].previousMicrosStop  = currentMicros; 
        
           } 
        
           #else   // #if USE_COMPLEX_STRUCT 
        
           irqCallback irqCallbackStartFunc[] = 
        
           { 
        
             doingSomethingStart0,  doingSomethingStart1,  doingSomethingStart2,  doingSomethingStart3, 
        
             doingSomethingStart4,  doingSomethingStart5,  doingSomethingStart6,  doingSomethingStart7 
        
           }; 
        
           irqCallback irqCallbackStopFunc[] = 
        
           { 
        
             doingSomethingStop0,  doingSomethingStop1,  doingSomethingStop2,  doingSomethingStop3, 
        
             doingSomethingStop4,  doingSomethingStop5,  doingSomethingStop6,  doingSomethingStop7 
        
           }; 
        
           #endif    // #if USE_COMPLEX_STRUCT 
        
           ////////////////////////////////////////////////////// 
        
           #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 previousMicrosStart = startMicros; 
        
             unsigned long currMicros = micros(); 
        
             Serial.print(F("SimpleTimer (ms): ")); Serial.print(SIMPLE_TIMER_MS); 
        
             Serial.print(F(", ms : ")); Serial.print(currMicros); 
        
             Serial.print(F(", Dms : ")); Serial.println(currMicros - previousMicrosStart); 
        
             for (uint16_t i = 0; i < NUMBER_ISR_PWMS; i++) 
        
             { 
        
           #if USE_COMPLEX_STRUCT 
        
               Serial.print(F("PWM Channel : ")); Serial.print(i); 
        
               Serial.print(F(", programmed Period (us): "));  
        
             #if USING_PWM_FREQUENCY 
        
               Serial.print(1000000 / curISR_PWM_Data[i].PWM_Freq); 
        
             #else 
        
               Serial.print(curISR_PWM_Data[i].PWM_Period); 
        
             #endif 
        
               Serial.print(F(", actual : ")); Serial.print(curISR_PWM_Data[i].deltaMicrosStart); 
        
               Serial.print(F(", programmed DutyCycle : "));  
        
               Serial.print(curISR_PWM_Data[i].PWM_DutyCycle); 
        
               Serial.print(F(", actual : ")); Serial.println((float) curISR_PWM_Data[i].deltaMicrosStop * 100.0f / curISR_PWM_Data[i].deltaMicrosStart); 
        
           #else 
        
               Serial.print(F("PWM Channel : ")); Serial.print(i); 
        
             #if USING_PWM_FREQUENCY 
        
               Serial.print(1000000.0 / PWM_Freq[i]); 
        
             #else 
        
               Serial.print(PWM_Period[i]); 
        
             #endif 
        
               Serial.print(F(", programmed Period (us): ")); Serial.print(PWM_Period[i]); 
        
               Serial.print(F(", actual : ")); Serial.print(deltaMicrosStart[i]); 
        
               Serial.print(F(", programmed DutyCycle : "));  
        
               Serial.print(PWM_DutyCycle[i]); 
        
               Serial.print(F(", actual : ")); Serial.println( (float) deltaMicrosStop[i] * 100.0f / deltaMicrosStart[i]); 
        
           #endif 
        
             } 
        
             previousMicrosStart = currMicros; 
        
           } 
        
           void setup() 
        
           { 
        
             Serial.begin(115200); 
        
             while (!Serial); 
        
             delay(2000); 
        
             Serial.print(F("\nStarting ISR_16_PWMs_Array_Complex on ")); Serial.println(ARDUINO_BOARD); 
        
             Serial.println(ESP8266_PWM_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)) 
        
             { 
        
               startMicros = micros(); 
        
               Serial.print(F("Starting ITimer OK, micros() = ")); Serial.println(startMicros); 
        
             } 
        
             else 
        
               Serial.println(F("Can't set ITimer. Select another freq. or timer")); 
        
             startMicros = micros(); 
        
             // Just to demonstrate, don't use too many ISR Timers if not absolutely necessary 
        
             // You can use up to 16 timer for each ISR_PWM 
        
             for (uint16_t i = 0; i < NUMBER_ISR_PWMS; i++) 
        
             { 
        
           #if USE_COMPLEX_STRUCT 
        
               curISR_PWM_Data[i].previousMicrosStart = startMicros; 
        
               //ISR_PWM.setInterval(curISR_PWM_Data[i].PWM_Period, curISR_PWM_Data[i].irqCallbackStartFunc); 
        
               //void setPWM(uint32_t pin, float frequency, float dutycycle 
        
               // , timer_callback_p StartCallback = nullptr, timer_callback_p StopCallback = nullptr) 
        
             #if USING_PWM_FREQUENCY 
        
               // You can use this with PWM_Freq in Hz 
        
               ISR_PWM.setPWM(curISR_PWM_Data[i].PWM_Pin, curISR_PWM_Data[i].PWM_Freq, curISR_PWM_Data[i].PWM_DutyCycle,  
        
                              curISR_PWM_Data[i].irqCallbackStartFunc, curISR_PWM_Data[i].irqCallbackStopFunc); 
        
             #else 
        
               // Or You can use this with PWM_Period in us 
        
               ISR_PWM.setPWM_Period(curISR_PWM_Data[i].PWM_Pin, curISR_PWM_Data[i].PWM_Period, curISR_PWM_Data[i].PWM_DutyCycle,  
        
                                     curISR_PWM_Data[i].irqCallbackStartFunc, curISR_PWM_Data[i].irqCallbackStopFunc); 
        
             #endif 
        
           #else 
        
               previousMicrosStart[i] = micros(); 
        
             #if USING_PWM_FREQUENCY 
        
               // You can use this with PWM_Freq in Hz 
        
               ISR_PWM.setPWM(PWM_Pin[i], PWM_Freq[i], PWM_DutyCycle[i], irqCallbackStartFunc[i], irqCallbackStopFunc[i]); 
        
             #else 
        
               // Or You can use this with PWM_Period in us 
        
               ISR_PWM.setPWM_Period(PWM_Pin[i], PWM_Period[i], PWM_DutyCycle[i], irqCallbackStartFunc[i], irqCallbackStopFunc[i]); 
        
             #endif  
        
           #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_PWM 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_PWM 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_PWM.run() here in the loop(). It's already handled by ISR timer. 
        
             simpleTimer.run(); 
        
           }

Debug Terminal Output Samples

1. ISR_16_PWMs_Array_Complex on ESP8266_NODEMCU_ESP12E

The following is the sample terminal output when running example ISR_16_PWMs_Array_Complex to demonstrate the accuracy of ISR Hardware PWM-channels, especially when system is very busy. The ISR PWM-channels is running exactly according to corresponding programmed periods

Starting ISR_16_PWMs_Array_Complex on ESP8266_NODEMCU_ESP12E
ESP8266_PWM v1.2.4
CPU Frequency = 160 MHz
[PWM] ESP8266TimerInterrupt: Timer Clock fre = 80000000
[PWM] Timer fre = 50000.00 , _count = 1600
Starting ITimer OK, micros() = 2073808
Channel : 0	    Period : 1000000		OnTime : 50000	Start_Time : 2077435
Channel : 1	    Period : 500000		OnTime : 50000	Start_Time : 2083470
Channel : 2	    Period : 333333		OnTime : 66666	Start_Time : 2089512
Channel : 3	    Period : 250000		OnTime : 75000	Start_Time : 2095588
Channel : 4	    Period : 200000		OnTime : 80000	Start_Time : 2101657
Channel : 5	    Period : 166666		OnTime : 74999	Start_Time : 2107738
Channel : 6	    Period : 142857		OnTime : 71428	Start_Time : 2113805
Channel : 7	    Period : 125000		OnTime : 68750	Start_Time : 2119875
SimpleTimer (ms): 2000, ms : 12126030, Dms : 10048756
PWM Channel : 0, programmed Period (us): 1000000.00, actual : 1000005, programmed DutyCycle : 5.00, actual : 5.00
PWM Channel : 1, programmed Period (us): 500000.00, actual : 500013, programmed DutyCycle : 10.00, actual : 10.00
PWM Channel : 2, programmed Period (us): 333333.34, actual : 333348, programmed DutyCycle : 20.00, actual : 20.00
PWM Channel : 3, programmed Period (us): 250000.00, actual : 250016, programmed DutyCycle : 30.00, actual : 29.99
PWM Channel : 4, programmed Period (us): 200000.00, actual : 200004, programmed DutyCycle : 40.00, actual : 39.99
PWM Channel : 5, programmed Period (us): 166666.67, actual : 166684, programmed DutyCycle : 45.00, actual : 44.99
PWM Channel : 6, programmed Period (us): 142857.14, actual : 142869, programmed DutyCycle : 50.00, actual : 49.99
PWM Channel : 7, programmed Period (us): 125000.00, actual : 125018, programmed DutyCycle : 55.00, actual : 54.99
SimpleTimer (ms): 2000, ms : 22199583, Dms : 10073553
PWM Channel : 0, programmed Period (us): 1000000.00, actual : 1000005, programmed DutyCycle : 5.00, actual : 5.00
PWM Channel : 1, programmed Period (us): 500000.00, actual : 500012, programmed DutyCycle : 10.00, actual : 10.00
PWM Channel : 2, programmed Period (us): 333333.34, actual : 333348, programmed DutyCycle : 20.00, actual : 20.00
PWM Channel : 3, programmed Period (us): 250000.00, actual : 250016, programmed DutyCycle : 30.00, actual : 29.99
PWM Channel : 4, programmed Period (us): 200000.00, actual : 200005, programmed DutyCycle : 40.00, actual : 39.99
PWM Channel : 5, programmed Period (us): 166666.67, actual : 166684, programmed DutyCycle : 45.00, actual : 44.99
PWM Channel : 6, programmed Period (us): 142857.14, actual : 142870, programmed DutyCycle : 50.00, actual : 49.99
PWM Channel : 7, programmed Period (us): 125000.00, actual : 125019, programmed DutyCycle : 55.00, actual : 54.99
SimpleTimer (ms): 2000, ms : 32273095, Dms : 10073512
PWM Channel : 0, programmed Period (us): 1000000.00, actual : 1000004, programmed DutyCycle : 5.00, actual : 5.00
PWM Channel : 1, programmed Period (us): 500000.00, actual : 500012, programmed DutyCycle : 10.00, actual : 10.00
PWM Channel : 2, programmed Period (us): 333333.34, actual : 333348, programmed DutyCycle : 20.00, actual : 20.00
PWM Channel : 3, programmed Period (us): 250000.00, actual : 250016, programmed DutyCycle : 30.00, actual : 29.99
PWM Channel : 4, programmed Period (us): 200000.00, actual : 200005, programmed DutyCycle : 40.00, actual : 39.99
PWM Channel : 5, programmed Period (us): 166666.67, actual : 166685, programmed DutyCycle : 45.00, actual : 44.99
PWM Channel : 6, programmed Period (us): 142857.14, actual : 142870, programmed DutyCycle : 50.00, actual : 49.99
PWM Channel : 7, programmed Period (us): 125000.00, actual : 125019, programmed DutyCycle : 55.00, actual : 54.99

2. ISR_16_PWMs_Array on ESP8266_NODEMCU_ESP12E

The following is the sample terminal output when running example ISR_16_PWMs_Array to demonstrate how to use multiple Hardware PWM channels.

Starting ISR_16_PWMs_Array on ESP8266_NODEMCU_ESP12E
ESP8266_PWM v1.2.4
CPU Frequency = 160 MHz
[PWM] ESP8266TimerInterrupt: Timer Clock fre = 80000000
[PWM] Timer fre = 50000.00 , _count = 1600
Starting ITimer OK, micros() = 2072589
Channel : 0	    Period : 1000000	OnTime : 50000	Start_Time : 2076168
Channel : 1	    Period : 500000		OnTime : 50000	Start_Time : 2082485
Channel : 2	    Period : 333333		OnTime : 66666	Start_Time : 2088818
Channel : 3	    Period : 250000		OnTime : 75000	Start_Time : 2095149
Channel : 4	    Period : 200000		OnTime : 80000	Start_Time : 2101479
Channel : 5	    Period : 166667		OnTime : 75000	Start_Time : 2107820
Channel : 6	    Period : 142857		OnTime : 71428	Start_Time : 2114152
Channel : 7	    Period : 125000		OnTime : 68750	Start_Time : 2120482

3. ISR_16_PWMs_Array_Simple on ESP8266_NODEMCU_ESP12E

The following is the sample terminal output when running example ISR_16_PWMs_Array_Simple to demonstrate how to use multiple Hardware PWM channels.

Starting ISR_16_PWMs_Array_Simple on ESP8266_NODEMCU_ESP12E
ESP8266_PWM v1.2.4
CPU Frequency = 160 MHz
[PWM] ESP8266TimerInterrupt: Timer Clock fre = 80000000
[PWM] Timer fre = 50000.00 , _count = 1600
Starting ITimer OK, micros() = 2073472
Channel : 0	    Period : 1000000	OnTime : 50000	Start_Time : 2077055
Channel : 1	    Period : 500000		OnTime : 50000	Start_Time : 2083379
Channel : 2	    Period : 333333		OnTime : 66666	Start_Time : 2089704
Channel : 3	    Period : 250000		OnTime : 75000	Start_Time : 2096036
Channel : 4	    Period : 200000		OnTime : 80000	Start_Time : 2102366
Channel : 5	    Period : 166667		OnTime : 75000	Start_Time : 2108707
Channel : 6	    Period : 142857		OnTime : 71428	Start_Time : 2115038
Channel : 7	    Period : 125000		OnTime : 68750	Start_Time : 2121369

4. ISR_Modify_PWM on ESP8266_NODEMCU_ESP12E

The following is the sample terminal output when running example ISR_Modify_PWM to demonstrate how to modify PWM settings on-the-fly without deleting the PWM channel

Starting ISR_Modify_PWM on ESP8266_NODEMCU_ESP12E
ESP8266_PWM v1.2.4
CPU Frequency = 160 MHz
[PWM] ESP8266TimerInterrupt: Timer Clock fre = 80000000
[PWM] Timer fre = 50000.00 , _count = 1600
Starting ITimer OK, micros() = 2072681
Using PWM Freq = 200.00, PWM DutyCycle = 1.00
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 2080334
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 12082106
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 22083353
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 32084600
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 42085847
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 52087094
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 62088341
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 72089588
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 82090835
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 92092082
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 102093328
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 112094575
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 122095822
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 132097069
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 142098316
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 152099563
Channel : 0	    Period : 5000		OnTime : 50	Start_Time : 162100810
Channel : 0	    Period : 10000		OnTime : 555	Start_Time : 172102056

5. ISR_Changing_PWM on ESP8266_NODEMCU_ESP12E

The following is the sample terminal output when running example ISR_Changing_PWM to demonstrate how to modify PWM settings on-the-fly by deleting the PWM channel and reinit the PWM channel

Starting ISR_Changing_PWM on ESP8266_NODEMCU_ESP12E
ESP8266_PWM v1.2.4
CPU Frequency = 160 MHz
[PWM] ESP8266TimerInterrupt: Timer Clock fre = 80000000
[PWM] Timer fre = 50000.00 , _count = 1600
Starting ITimer OK, micros() = 2073309
Using PWM Freq = 1.00, PWM DutyCycle = 50.00
Channel : 0	    Period : 1000000		OnTime : 500000	Start_Time : 2080902
Using PWM Freq = 2.00, PWM DutyCycle = 90.00
Channel : 0	    Period : 500000		OnTime : 450000	Start_Time : 12087445
Using PWM Freq = 1.00, PWM DutyCycle = 50.00
Channel : 0	    Period : 1000000		OnTime : 500000	Start_Time : 22087762
Using PWM Freq = 2.00, PWM DutyCycle = 90.00
Channel : 0	    Period : 500000		OnTime : 450000	Start_Time : 32088065
Using PWM Freq = 1.00, PWM DutyCycle = 50.00
Channel : 0	    Period : 1000000		OnTime : 500000	Start_Time : 42088370
Using PWM Freq = 2.00, PWM DutyCycle = 90.00
Channel : 0	    Period : 500000		OnTime : 450000	Start_Time : 52088673
Using PWM Freq = 1.00, PWM DutyCycle = 50.00
Channel : 0	    Period : 1000000		OnTime : 500000	Start_Time : 62088982
Using PWM Freq = 2.00, PWM DutyCycle = 90.00
Channel : 0	    Period : 500000		OnTime : 450000	Start_Time : 72089285
Using PWM Freq = 1.00, PWM DutyCycle = 50.00
Channel : 0	    Period : 1000000		OnTime : 500000	Start_Time : 82089593
Using PWM Freq = 2.00, PWM DutyCycle = 90.00
Channel : 0	    Period : 500000		OnTime : 450000	Start_Time : 92089898
Using PWM Freq = 1.00, PWM DutyCycle = 50.00
Channel : 0	    Period : 1000000		OnTime : 500000	Start_Time : 102090204

Debug

Debug is enabled by default on Serial.

You can also change the debugging level _PWM_LOGLEVEL_ from 0 to 4

// These define's must be placed at the beginning before #include "ESP8266_PWM.h"
// _PWM_LOGLEVEL_ from 0 to 4
// Don't define _PWM_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system.
#define _PWM_LOGLEVEL_      4

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: ESP8266_PWM issues

TO DO

Search for bug and improvement.
Similar features for remaining Arduino boards such as SAMD21, SAMD51, SAM-DUE, nRF52, STM32, Portenta_H7, RP2040, etc.

DONE

Basic hardware PWM-channels for ESP8266 for ESP8266 core v3.0.2+
Longer time interval
Add complex examples.
Add functions to modify PWM settings on-the-fly
Improve accuracy by using float, instead of uint32_t for dutycycle
Optimize library code by using reference-passing instead of value-passing
DutyCycle to be optionally updated at the end current PWM period instead of immediately.
Display informational warning only when _PWM_LOGLEVEL_ > 3

Contributions and Thanks

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

Thanks to AnselPeng2019 to request new feature to modify PWM settings on-the-fly in

Change Duty Cycle #1 leading to v1.1.0

Thanks to ggmichael to request better PWM resolution, leading to v1.2.0, in

Change Duty Cycle #1

and enhancement request as well as testing to verify, leading to v1.2.2, in

DutyCycle to be updated at the end current PWM period #2

_{AnselPeng2019}

_ggmichael

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

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

README.md

README.md

ESP8266_PWM Library

Table of Contents

Important Change from v1.2.0

Why do we need this ESP8266_PWM library

Features

Why using ISR-based PWM-channels 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

More useful Information

Examples:

Example ISR_16_PWMs_Array_Complex

Debug Terminal Output Samples

1. ISR_16_PWMs_Array_Complex on ESP8266_NODEMCU_ESP12E

2. ISR_16_PWMs_Array on ESP8266_NODEMCU_ESP12E

3. ISR_16_PWMs_Array_Simple on ESP8266_NODEMCU_ESP12E

4. ISR_Modify_PWM on ESP8266_NODEMCU_ESP12E

5. ISR_Changing_PWM on ESP8266_NODEMCU_ESP12E

Debug

Troubleshooting

Issues

TO DO

DONE

Contributions and Thanks

Contributing

License

Copyright

	#if !defined(ESP8266)
	#error This code is designed to run on ESP8266 and ESP8266-based boards! Please check your Tools->Board setting.
	#endif

	// These define's must be placed at the beginning before #include "ESP8266_PWM.h"
	// _PWM_LOGLEVEL_ from 0 to 4
	// Don't define _PWM_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system.
	#define _PWM_LOGLEVEL_ 4

	#define USING_MICROS_RESOLUTION true //false

	// Default is true, uncomment to false
	//#define CHANGING_PWM_END_OF_CYCLE false

	// Select a Timer Clock
	#define USING_TIM_DIV1 true // for shortest and most accurate timer
	#define USING_TIM_DIV16 false // for medium time and medium accurate timer
	#define USING_TIM_DIV256 false // for longest timer but least accurate. Default

	// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
	#include "ESP8266_PWM.h"

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

	#ifndef LED_BUILTIN
	#define LED_BUILTIN 2
	#endif

	#define HW_TIMER_INTERVAL_US 20L

	volatile uint32_t startMicros = 0;

	// Init ESP8266Timer
	ESP8266Timer ITimer;

	// Init ESP8266_ISR_PWM
	ESP8266_PWM ISR_PWM;

	void IRAM_ATTR TimerHandler()
	{
	ISR_PWM.run();
	}

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

	#define NUMBER_ISR_PWMS 8

	//PIN_D0 can't be used for PWM/I2C
	#define PIN_D0 16 // Pin D0 mapped to pin GPIO16/USER/WAKE of ESP8266. This pin is also used for Onboard-Blue LED. PIN_D0 = 0 => LED ON
	#define PIN_D1 5 // Pin D1 mapped to pin GPIO5 of ESP8266
	#define PIN_D2 4 // Pin D2 mapped to pin GPIO4 of ESP8266
	#define PIN_D3 0 // Pin D3 mapped to pin GPIO0/FLASH of ESP8266
	#define PIN_D4 2 // Pin D4 mapped to pin GPIO2/TXD1 of ESP8266
	//#define PIN_LED 2 // Pin D4 mapped to pin GPIO2/TXD1 of ESP8266, NodeMCU and WeMoS, control on-board LED
	#define PIN_D5 14 // Pin D5 mapped to pin GPIO14/HSCLK of ESP8266
	#define PIN_D6 12 // Pin D6 mapped to pin GPIO12/HMISO of ESP8266
	#define PIN_D7 13 // Pin D7 mapped to pin GPIO13/RXD2/HMOSI of ESP8266
	#define PIN_D8 15 // Pin D8 mapped to pin GPIO15/TXD2/HCS of ESP8266
	#define PIN_D9 3 // Pin D9 /RX mapped to pin GPIO3/RXD0 of ESP8266
	#define PIN_D10 1 // Pin D10/TX mapped to pin GPIO1/TXD0 of ESP8266

	//Don't use pins GPIO6 to GPIO11 as already connected to flash, etc. Use them can crash the program
	//GPIO9(D11/SD2) and GPIO11 can be used only if flash in DIO mode ( not the default QIO mode)
	#define PIN_D11 9 // Pin D11/SD2 mapped to pin GPIO9/SDD2 of ESP8266
	#define PIN_D12 10 // Pin D12/SD3 mapped to pin GPIO10/SDD3 of ESP8266

	typedef void (*irqCallback) ();

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

	#define USE_COMPLEX_STRUCT true

	#define USING_PWM_FREQUENCY true

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

	#if USE_COMPLEX_STRUCT

	typedef struct
	{
	uint32_t PWM_Pin;
	irqCallback irqCallbackStartFunc;
	irqCallback irqCallbackStopFunc;

	#if USING_PWM_FREQUENCY
	float PWM_Freq;
	#else
	uint32_t PWM_Period;
	#endif

	float PWM_DutyCycle;

	uint64_t deltaMicrosStart;
	uint64_t previousMicrosStart;

	uint64_t deltaMicrosStop;
	uint64_t previousMicrosStop;
	} ISR_PWM_Data;

	// 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 doingSomethingStart(int index);

	void doingSomethingStop(int index);

	#else // #if USE_COMPLEX_STRUCT

	volatile unsigned long deltaMicrosStart [] = { 0, 0, 0, 0, 0, 0, 0, 0 };
	volatile unsigned long previousMicrosStart [] = { 0, 0, 0, 0, 0, 0, 0, 0 };

	volatile unsigned long deltaMicrosStop [] = { 0, 0, 0, 0, 0, 0, 0, 0 };
	volatile unsigned long previousMicrosStop [] = { 0, 0, 0, 0, 0, 0, 0, 0 };

	// You can assign pins here. Be carefull to select good pin to use or crash
	uint32_t PWM_Pin[] =
	{
	PIN_D0, PIN_D1, LED_BUILTIN, PIN_D3, PIN_D4, PIN_D5, PIN_D6, PIN_D7
	};

	// You can assign any interval for any timer here, in microseconds
	uint32_t PWM_Period[] =
	{
	1000000, 500000, 333333, 250000, 200000, 166667, 142857, 125000
	};

	// You can assign any interval for any timer here, in Hz
	float PWM_Freq[] =
	{
	1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0
	};

	// You can assign any interval for any timer here, in Microseconds
	float PWM_DutyCycle[] =
	{
	5.0, 10.0, 20.0, 30.0, 40.0, 45.0, 50.0, 55.0
	};

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

	void doingSomethingStart(int index)
	{
	unsigned long currentMicros = micros();

	deltaMicrosStart[index] = currentMicros - previousMicrosStart[index];
	previousMicrosStart[index] = currentMicros;
	}

	void doingSomethingStop(int index)
	{
	unsigned long currentMicros = micros();

	//deltaMicrosStop[index] = currentMicros - previousMicrosStop[index];
	// Count from start to stop PWM pulse
	deltaMicrosStop[index] = currentMicros - previousMicrosStart[index];
	previousMicrosStop[index] = currentMicros;
	}

	#endif // #if USE_COMPLEX_STRUCT

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

	void doingSomethingStart0()
	{
	doingSomethingStart(0);
	}

	void doingSomethingStart1()
	{
	doingSomethingStart(1);
	}

	void doingSomethingStart2()
	{
	doingSomethingStart(2);
	}

	void doingSomethingStart3()
	{
	doingSomethingStart(3);
	}

	void doingSomethingStart4()
	{
	doingSomethingStart(4);
	}

	void doingSomethingStart5()
	{
	doingSomethingStart(5);
	}

	void doingSomethingStart6()
	{
	doingSomethingStart(6);
	}

	void doingSomethingStart7()
	{
	doingSomethingStart(7);
	}

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

	void doingSomethingStop0()
	{
	doingSomethingStop(0);
	}

	void doingSomethingStop1()
	{
	doingSomethingStop(1);
	}

	void doingSomethingStop2()
	{
	doingSomethingStop(2);
	}

	void doingSomethingStop3()
	{
	doingSomethingStop(3);
	}

	void doingSomethingStop4()
	{
	doingSomethingStop(4);
	}

	void doingSomethingStop5()
	{
	doingSomethingStop(5);
	}

	void doingSomethingStop6()
	{
	doingSomethingStop(6);
	}

	void doingSomethingStop7()
	{
	doingSomethingStop(7);
	}

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

	#if USE_COMPLEX_STRUCT

	#if USING_PWM_FREQUENCY

	ISR_PWM_Data curISR_PWM_Data[] =
	{
	//pin, irqCallbackStartFunc, irqCallbackStopFunc, PWM_Freq, PWM_DC, deltaMicrosStart, previousMicrosStart, deltaMicrosStop, previousMicrosStop
	{ PIN_D0, doingSomethingStart0, doingSomethingStop0, 1.0, 5.0, 0, 0, 0, 0 },
	{ PIN_D1, doingSomethingStart1, doingSomethingStop1, 2.0, 10.0, 0, 0, 0, 0 },
	{ LED_BUILTIN, doingSomethingStart2, doingSomethingStop2, 3.0, 20.0, 0, 0, 0, 0 },
	{ PIN_D3, doingSomethingStart3, doingSomethingStop3, 4.0, 30.0, 0, 0, 0, 0 },
	{ PIN_D4, doingSomethingStart4, doingSomethingStop4, 5.0, 40.0, 0, 0, 0, 0 },
	{ PIN_D5, doingSomethingStart5, doingSomethingStop5, 6.0, 45.0, 0, 0, 0, 0 },
	{ PIN_D6, doingSomethingStart6, doingSomethingStop6, 7.0, 50.0, 0, 0, 0, 0 },
	{ PIN_D7, doingSomethingStart7, doingSomethingStop7, 8.0, 55.0, 0, 0, 0, 0 },
	};

	#else // #if USING_PWM_FREQUENCY

	ISR_PWM_Data curISR_PWM_Data[] =
	{
	//pin, irqCallbackStartFunc, irqCallbackStopFunc, PWM_Period, PWM_DC, deltaMicrosStart, previousMicrosStart, deltaMicrosStop, previousMicrosStop
	{ PIN_D0, doingSomethingStart0, doingSomethingStop0, 1000000, 5.0, 0, 0, 0, 0 },
	{ PIN_D1, doingSomethingStart1, doingSomethingStop1, 500000, 10.0, 0, 0, 0, 0 },
	{ LED_BUILTIN, doingSomethingStart2, doingSomethingStop2, 333333, 20.0, 0, 0, 0, 0 },
	{ PIN_D3, doingSomethingStart3, doingSomethingStop3, 250000, 30.0, 0, 0, 0, 0 },
	{ PIN_D4, doingSomethingStart4, doingSomethingStop4, 200000, 40.0, 0, 0, 0, 0 },
	{ PIN_D5, doingSomethingStart5, doingSomethingStop5, 166667, 45.0, 0, 0, 0, 0 },
	{ PIN_D6, doingSomethingStart6, doingSomethingStop6, 142857, 50.0, 0, 0, 0, 0 },
	{ PIN_D7, doingSomethingStart7, doingSomethingStop7, 125000 55.0, 0, 0, 0, 0 },
	};

	#endif // #if USING_PWM_FREQUENCY

	void doingSomethingStart(int index)
	{
	unsigned long currentMicros = micros();

	curISR_PWM_Data[index].deltaMicrosStart = currentMicros - curISR_PWM_Data[index].previousMicrosStart;
	curISR_PWM_Data[index].previousMicrosStart = currentMicros;
	}

	void doingSomethingStop(int index)
	{
	unsigned long currentMicros = micros();

	//curISR_PWM_Data[index].deltaMicrosStop = currentMicros - curISR_PWM_Data[index].previousMicrosStop;
	// Count from start to stop PWM pulse
	curISR_PWM_Data[index].deltaMicrosStop = currentMicros - curISR_PWM_Data[index].previousMicrosStart;
	curISR_PWM_Data[index].previousMicrosStop = currentMicros;
	}

	#else // #if USE_COMPLEX_STRUCT

	irqCallback irqCallbackStartFunc[] =
	{
	doingSomethingStart0, doingSomethingStart1, doingSomethingStart2, doingSomethingStart3,
	doingSomethingStart4, doingSomethingStart5, doingSomethingStart6, doingSomethingStart7
	};

	irqCallback irqCallbackStopFunc[] =
	{
	doingSomethingStop0, doingSomethingStop1, doingSomethingStop2, doingSomethingStop3,
	doingSomethingStop4, doingSomethingStop5, doingSomethingStop6, doingSomethingStop7
	};

	#endif // #if USE_COMPLEX_STRUCT

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

	#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 previousMicrosStart = startMicros;

	unsigned long currMicros = micros();

	Serial.print(F("SimpleTimer (ms): ")); Serial.print(SIMPLE_TIMER_MS);
	Serial.print(F(", ms : ")); Serial.print(currMicros);
	Serial.print(F(", Dms : ")); Serial.println(currMicros - previousMicrosStart);

	for (uint16_t i = 0; i < NUMBER_ISR_PWMS; i++)
	{
	#if USE_COMPLEX_STRUCT
	Serial.print(F("PWM Channel : ")); Serial.print(i);
	Serial.print(F(", programmed Period (us): "));

	#if USING_PWM_FREQUENCY
	Serial.print(1000000 / curISR_PWM_Data[i].PWM_Freq);
	#else
	Serial.print(curISR_PWM_Data[i].PWM_Period);
	#endif

	Serial.print(F(", actual : ")); Serial.print(curISR_PWM_Data[i].deltaMicrosStart);

	Serial.print(F(", programmed DutyCycle : "));

	Serial.print(curISR_PWM_Data[i].PWM_DutyCycle);

	Serial.print(F(", actual : ")); Serial.println((float) curISR_PWM_Data[i].deltaMicrosStop * 100.0f / curISR_PWM_Data[i].deltaMicrosStart);

	#else

	Serial.print(F("PWM Channel : ")); Serial.print(i);

	#if USING_PWM_FREQUENCY
	Serial.print(1000000.0 / PWM_Freq[i]);
	#else
	Serial.print(PWM_Period[i]);
	#endif

	Serial.print(F(", programmed Period (us): ")); Serial.print(PWM_Period[i]);
	Serial.print(F(", actual : ")); Serial.print(deltaMicrosStart[i]);

	Serial.print(F(", programmed DutyCycle : "));

	Serial.print(PWM_DutyCycle[i]);

	Serial.print(F(", actual : ")); Serial.println( (float) deltaMicrosStop[i] * 100.0f / deltaMicrosStart[i]);
	#endif
	}

	previousMicrosStart = currMicros;
	}

	void setup()
	{
	Serial.begin(115200);
	while (!Serial);

	delay(2000);

	Serial.print(F("\nStarting ISR_16_PWMs_Array_Complex on ")); Serial.println(ARDUINO_BOARD);
	Serial.println(ESP8266_PWM_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))
	{
	startMicros = micros();
	Serial.print(F("Starting ITimer OK, micros() = ")); Serial.println(startMicros);
	}
	else
	Serial.println(F("Can't set ITimer. Select another freq. or timer"));

	startMicros = micros();

	// Just to demonstrate, don't use too many ISR Timers if not absolutely necessary
	// You can use up to 16 timer for each ISR_PWM

	for (uint16_t i = 0; i < NUMBER_ISR_PWMS; i++)
	{
	#if USE_COMPLEX_STRUCT
	curISR_PWM_Data[i].previousMicrosStart = startMicros;
	//ISR_PWM.setInterval(curISR_PWM_Data[i].PWM_Period, curISR_PWM_Data[i].irqCallbackStartFunc);

	//void setPWM(uint32_t pin, float frequency, float dutycycle
	// , timer_callback_p StartCallback = nullptr, timer_callback_p StopCallback = nullptr)

	#if USING_PWM_FREQUENCY
	// You can use this with PWM_Freq in Hz
	ISR_PWM.setPWM(curISR_PWM_Data[i].PWM_Pin, curISR_PWM_Data[i].PWM_Freq, curISR_PWM_Data[i].PWM_DutyCycle,
	curISR_PWM_Data[i].irqCallbackStartFunc, curISR_PWM_Data[i].irqCallbackStopFunc);
	#else
	// Or You can use this with PWM_Period in us
	ISR_PWM.setPWM_Period(curISR_PWM_Data[i].PWM_Pin, curISR_PWM_Data[i].PWM_Period, curISR_PWM_Data[i].PWM_DutyCycle,
	curISR_PWM_Data[i].irqCallbackStartFunc, curISR_PWM_Data[i].irqCallbackStopFunc);
	#endif

	#else
	previousMicrosStart[i] = micros();

	#if USING_PWM_FREQUENCY
	// You can use this with PWM_Freq in Hz
	ISR_PWM.setPWM(PWM_Pin[i], PWM_Freq[i], PWM_DutyCycle[i], irqCallbackStartFunc[i], irqCallbackStopFunc[i]);
	#else
	// Or You can use this with PWM_Period in us
	ISR_PWM.setPWM_Period(PWM_Pin[i], PWM_Period[i], PWM_DutyCycle[i], irqCallbackStartFunc[i], irqCallbackStopFunc[i]);
	#endif

	#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_PWM 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_PWM 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_PWM.run() here in the loop(). It's already handled by ISR timer.
	simpleTimer.run();
	}

Files

README.md

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README.md

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ESP8266_PWM Library

Table of Contents

Important Change from v1.2.0

Why do we need this ESP8266_PWM library

Features

Why using ISR-based PWM-channels 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

More useful Information

Examples:

Example ISR_16_PWMs_Array_Complex

Debug Terminal Output Samples

1. ISR_16_PWMs_Array_Complex on ESP8266_NODEMCU_ESP12E

2. ISR_16_PWMs_Array on ESP8266_NODEMCU_ESP12E

3. ISR_16_PWMs_Array_Simple on ESP8266_NODEMCU_ESP12E

4. ISR_Modify_PWM on ESP8266_NODEMCU_ESP12E

5. ISR_Changing_PWM on ESP8266_NODEMCU_ESP12E

Debug

Troubleshooting

Issues

TO DO

DONE

Contributions and Thanks

Contributing

License

Copyright

HOWTO Fix `Multiple Definitions` Linker Error