ESP32_FastPWM Library

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Table of Contents

• Why do we need this ESP32_FastPWM library
  • Features
  • Why using hardware-based PWM is better
  • Currently supported Boards
• Changelog
• Prerequisites
• Installation
  • Use Arduino Library Manager
  • Manual Install
  • VS Code & PlatformIO
• 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
• Usage
  • 1. Create PWM Instance with Pin, Frequency, dutycycle, channel (default = 0) and PWM_resolution (default = 8)
  • 2. Initialize PWM Instance
  • 3. Set or change PWM frequency or dutyCycle
  • 4. Set or change PWM frequency and dutyCycle manually and efficiently in waveform creation
• Examples
  • 1. PWM_Basic
  • 2. PWM_DynamicDutyCycle
  • 3. PWM_DynamicDutyCycle_Int
  • 4. PWM_DynamicFreq
  • 5. PWM_Multi
  • 6. PWM_MultiChannel
  • 7. PWM_Waveform
  • 8. PWM_StepperControl New
  • 9. PWM_manual New
• Example PWM_Multi
• Debug Terminal Output Samples
  • 1. PWM_DynamicDutyCycle on ESP32_DEV
  • 2. PWM_Multi on ESP32_DEV
  • 3. PWM_DynamicFreq on ESP32S3_DEV
  • 4. PWM_Waveform on ESP32S2_DEV
  • 5. PWM_Waveform on ESP32C3_DEV
  • 6. PWM_Waveform on ESP32S3_DEV
  • 7. PWM_manual on ESP32_DEV
• Debug
• Troubleshooting
• Issues
• TO DO
• DONE
• Contributions and Thanks
• Contributing
• License
• Copyright

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Why do we need this ESP32_FastPWM library

Features

This hardware-based PWM library, a wrapper and enhancement around ESP32-core ledc code, enables you to use Hardware-PWM on ESP32, ESP32_S2, ESP32_S3 and ESP32_C3 boards to create and output PWM. These purely hardware-based PWM channels can generate very high PWM frequencies, depending on CPU clock and acceptable accuracy. The maximum resolution can be 20-bit with very low frequencies. Normally 8, 12 or 16-bit resolution is good enough.

// Max resolution is 20-bit
// Resolution 65536 (16-bit) for lower frequencies, OK @ 1K
// Resolution  4096 (12-bit) for lower frequencies, OK @ 10K
// Resolution  1024 (10-bit) for higher frequencies, OK @ 50K
// Resolution  256  ( 8-bit)for higher frequencies, OK @ 100K, 200K
// Resolution  128  ( 7-bit) for higher frequencies, OK @ 500K

This library is using the same or similar functions as other FastPWM libraries, as follows, to enable you to port your PWM code easily between platforms

1. RP2040_PWM
2. AVR_PWM
3. megaAVR_PWM
4. ESP32_FastPWM
5. SAMD_PWM
6. SAMDUE_PWM
7. nRF52_PWM
8. Teensy_PWM
9. ATtiny_PWM
10. Dx_PWM
11. Portenta_H7_PWM
12. MBED_RP2040_PWM
13. nRF52_MBED_PWM
14. STM32_PWM

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The most important feature is they're purely hardware-based PWM channels. Therefore, their operations are not blocked by bad-behaving software functions / tasks.

This important feature is absolutely necessary for mission-critical tasks. These hardware PWM-channels, still work even if other software 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 control external systems (Servo, etc.) requiring better accuracy.

New efficient setPWM_manual() and setPWM_DCPercentage_manual() functions enable waveform creation using PWM.

The PWM_Multi example will demonstrate the usage of multichannel PWM using multiple Hardware-PWM blocks (slices). The 4 independent Hardware-PWM channels are used to control 4 different PWM outputs, with totally independent frequencies and dutycycles on ESP32.

Being hardware-based PWM, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet or Blynk services.

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

Why using hardware-based PWM is better

Imagine you have a system with a mission-critical function, controlling a robot 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 hardware-based PWM.

These hardware-based PWM channels still work even if other software functions are blocking. Moreover, they are much more precise (certainly depending on clock frequency accuracy) than other software-based PWMs, using millis() or micros().

Functions using normal software-based PWMs, 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.

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Currently supported Boards

1. ESP32 boards, such as ESP32_DEV, etc.
2. ESP32S2-based boards, such as ESP32S2_DEV, ESP32_S2 Saola, Adafruit QTPY_ESP32S2, etc.
3. ESP32C3-based boards, such as ESP32C3_DEV, etc.
4. ESP32_S3 (ESP32S3_DEV, ESP32_S3_BOX, UM TINYS3, UM PROS3, UM FEATHERS3, FEATHER_ESP32S3_NOPSRAM and QTPY_ESP32S3_NOPSRAM, etc.)

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Prerequisites

1. Arduino IDE 1.8.19+ for Arduino.
2. ESP32 Core 2.0.6+ for ESP32-based boards. .

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Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for ESP32_FastPWM, then select / install the latest version. You can also use this link for more detailed instructions.

Manual Install

Another way to install is to:

1. Navigate to ESP32_FastPWM page.
2. Download the latest release ESP32_FastPWM-main.zip.
3. Extract the zip file to ESP32_FastPWM-main directory
4. Copy whole ESP32_FastPWM-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO

1. Install VS Code
2. Install PlatformIO
3. Install ESP32_FastPWM library by using Library Manager. Search for ESP32_FastPWM in Platform.io Author's Libraries
4. 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

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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:

1. 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.

2. 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)

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More useful Information

ESP32 Hardware Timers

• The ESP32, ESP32_S2 and ESP32_S3 has two timer groups, each one with two general purpose hardware timers.
• The ESP32_C3 has two timer groups, each one with only one general purpose hardware timer.
• All the timers are based on 64-bit counters (except 54-bit counter for ESP32_S3 counter) 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.

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Usage

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

// Max resolution is 20-bit
// Resolution 65536 (16-bit) for lower frequencies, OK @ 1K
// Resolution  4096 (12-bit) for lower frequencies, OK @ 10K
// Resolution  1024 (10-bit) for higher frequencies, OK @ 50K
// Resolution  256  ( 8-bit)for higher frequencies, OK @ 100K, 200K
// Resolution  128  ( 7-bit) for higher frequencies, OK @ 500K

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

// All GPIO pins (but GPIO34-39) can be used to generate PWM
// For ESP32, number of channels is 16, max 20-bit resolution
// For ESP32_S2, ESP32_S3, number of channels is 8, max 20-bit resolution
// For ESP32_C3, number of channels is 6, max 20-bit resolution

1. Create PWM Instance with Pin, Frequency, dutycycle, channel (default = 0) and PWM_resolution (default = 8)

ESP32_FAST_PWM* PWM_Instance;

PWM_Instance = new ESP32_FAST_PWM(pinToUse, frequency, dutyCycle, channel, PWM_resolution);

2. Initialize PWM Instance

if (PWM_Instance)
{
  PWM_Instance->setPWM();
}

3. Set or change PWM frequency or dutyCycle

To use float new_dutyCycle

PWM_Instance->setPWM(PWM_Pins, new_frequency, new_dutyCycle);

such as

dutyCycle = 10.0f;
  
Serial.print(F("Change PWM DutyCycle to ")); Serial.println(dutyCycle);
PWM_Instance->setPWM(pinToUse, frequency, dutyCycle);

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To use uint32_t new_dutyCycle = (real_dutyCycle * 65536) / 100

PWM_Instance->setPWM_Int(PWM_Pins, new_frequency, new_dutyCycle);

such as for real_dutyCycle = 50%

// 50% dutyCycle = (real_dutyCycle * 65536) / 100
dutyCycle = 32768;

Serial.print(F("Change PWM DutyCycle to (%) "));
Serial.println((float) dutyCycle * 100 / 65536);
PWM_Instance->setPWM_Int(pinToUse, frequency, dutyCycle);

for real_dutyCycle = 50%

// 20% dutyCycle = (real_dutyCycle * 65536) / 100
dutyCycle = 13107;

Serial.print(F("Change PWM DutyCycle to (%) "));
Serial.println((float) dutyCycle * 100 / 65536);
PWM_Instance->setPWM_Int(pinToUse, frequency, dutyCycle);

4. Set or change PWM frequency and dutyCycle manually and efficiently in waveform creation

Function prototype

bool setPWM_manual(const uint8_t& pin, const uint16_t& DCValue);
bool setPWM_DCPercentage_manual(const uint8_t& pin, const float& DCPercentage);

Need to call only once for each pin

PWM_Instance->setPWM(PWM_Pins, frequency, dutyCycle);

after that, if just changing dutyCycle / level, use

// For 50.0f dutycycle
new_level = 50.0f * ( 1 << PWM_Instance->getResolution() ) / 100.0f ;
PWM_Instance->setPWM_manual(PWM_Pins, new_level);

or better and much easier to use

new_DCPercentage = 50.0f;
PWM_Instance->setPWM_DCPercentage_manual(PWM_Pins, new_DCPercentage);

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Examples:

1. PWM_Basic
2. PWM_DynamicDutyCycle
3. PWM_DynamicDutyCycle_Int
4. PWM_DynamicFreq
5. PWM_Multi
6. PWM_MultiChannel
7. PWM_Waveform
8. PWM_StepperControl New
9. PWM_manual New

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Example PWM_Multi

ESP32_FastPWM/examples/PWM_Multi/PWM_Multi.ino

Lines 12 to 153 in 09ea7da

	/******************************************************************************************************************************
	// All GPIO pins (but GPIO34-39) can be used to generate PWM
	// For ESP32, number of channels is 16, max 20-bit resolution
	// For ESP32_S2, ESP32_S3, number of channels is 8
	// For ESP32_C3, number of channels is 6
	LEDC Chan to Group/Channel/Timer Mapping
	** ledc: 0 => Group: 0, Channel: 0, Timer: 0
	** ledc: 1 => Group: 0, Channel: 1, Timer: 0
	** ledc: 2 => Group: 0, Channel: 2, Timer: 1
	** ledc: 3 => Group: 0, Channel: 3, Timer: 1
	** ledc: 4 => Group: 0, Channel: 4, Timer: 2
	** ledc: 5 => Group: 0, Channel: 5, Timer: 2
	** ledc: 6 => Group: 0, Channel: 6, Timer: 3
	** ledc: 7 => Group: 0, Channel: 7, Timer: 3
	** ledc: 8 => Group: 1, Channel: 0, Timer: 0
	** ledc: 9 => Group: 1, Channel: 1, Timer: 0
	** ledc: 10 => Group: 1, Channel: 2, Timer: 1
	** ledc: 11 => Group: 1, Channel: 3, Timer: 1
	** ledc: 12 => Group: 1, Channel: 4, Timer: 2
	** ledc: 13 => Group: 1, Channel: 5, Timer: 2
	** ledc: 14 => Group: 1, Channel: 6, Timer: 3
	** ledc: 15 => Group: 1, Channel: 7, Timer: 3
	******************************************************************************************************************************/
	#define _PWM_LOGLEVEL_ 4
	#include "ESP32_FastPWM.h"
	#define pinToUse 16
	// Max resolution is 20-bit
	// Resolution 65536 (16-bit) for lower frequencies, OK @ 1K
	// Resolution 4096 (12-bit) for lower frequencies, OK @ 10K
	// Resolution 1024 (10-bit) for higher frequencies, OK @ 50K
	// Resolution 256 ( 8-bit)for higher frequencies, OK @ 100K, 200K
	// Resolution 128 ( 7-bit) for higher frequencies, OK @ 500K
	int PWM_resolution = 12;
	#if ARDUINO_ESP32C3_DEV
	uint32_t PWM_Pins[] = { 8, 9, 2, 3 };
	#else
	uint32_t PWM_Pins[] = { 16, 17, 19, 21 };
	#endif
	// Must use different group-timer for different frequency
	// e.g. chan 0 (Group0-T0) and chan8(Group1-T0) OK for dif. freq, but not chan0(Group0-T0) and chan1(Group0-T0)
	// timer = ((chan / 2) % 4)
	// group = (chan / 8)
	// For ESP32
	// Group 0: channel 0-1 => timer0, channel 2-3 => timer1, channel 4-5 => timer2, channel 6-7 => timer3
	// Group 1: channel 8-9 => timer0, channel 10-11 => timer1, channel 12-13 => timer2, channel 14-15 => timer3
	uint32_t PWM_chan[] = { 0, 2, 4, 6 };
	// Still OK if different freq
	//uint32_t PWM_chan[] = { 0, 8, 4, 6 };
	// Not OK if different freq
	//uint32_t PWM_chan[] = { 0, 1, 4, 6 };
	#define NUM_OF_PINS ( sizeof(PWM_Pins) / sizeof(uint32_t) )
	float dutyCycle[] = { 10.0f, 30.0f, 50.0f, 90.0f };
	float frequency[] = { 2000.0f, 3000.0f, 4000.0f, 8000.0f };
	ESP32_FAST_PWM* PWM_Instance[NUM_OF_PINS];
	char dashLine[] = "=====================================================================================";
	void printPWMInfo(ESP32_FAST_PWM* PWM_Instance)
	{
	Serial.println(dashLine);
	Serial.print("Actual data: pin = ");
	Serial.print(PWM_Instance->getPin());
	Serial.print(", PWM DC = ");
	Serial.print(PWM_Instance->getActualDutyCycle());
	Serial.print(", PWMPeriod = ");
	Serial.print(PWM_Instance->getPWMPeriod());
	Serial.print(", PWM Freq (Hz) = ");
	Serial.println(PWM_Instance->getActualFreq(), 4);
	Serial.println(dashLine);
	}
	void setup()
	{
	Serial.begin(115200);
	while (!Serial && millis() < 5000);
	delay(500);
	Serial.print(F("\nStarting PWM_Multi on "));
	Serial.println(ARDUINO_BOARD);
	Serial.println(ESP32_FAST_PWM_VERSION);
	for (uint8_t index = 0; index < NUM_OF_PINS; index++)
	{
	PWM_Instance[index] = new ESP32_FAST_PWM(PWM_Pins[index], frequency[index], dutyCycle[index], PWM_chan[index],
	PWM_resolution);
	if (PWM_Instance[index])
	{
	PWM_Instance[index]->setPWM();
	}
	}
	Serial.println(dashLine);
	Serial.println("Index\tPin\tPWM_freq\tDutyCycle\tActual Freq");
	Serial.println(dashLine);
	for (uint8_t index = 0; index < NUM_OF_PINS; index++)
	{
	if (PWM_Instance[index])
	{
	Serial.print(index);
	Serial.print("\t");
	Serial.print(PWM_Pins[index]);
	Serial.print("\t");
	Serial.print(frequency[index]);
	Serial.print("\t\t");
	Serial.print(dutyCycle[index]);
	Serial.print("\t\t");
	Serial.println(PWM_Instance[index]->getActualFreq(), 4);
	}
	else
	{
	Serial.println();
	}
	}
	for (uint8_t index = 0; index < NUM_OF_PINS; index++)
	{
	printPWMInfo(PWM_Instance[index]);
	}
	}
	void loop()
	{
	//Long delay has no effect on the operation of hardware-based PWM channels
	delay(1000000);
	}

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Debug Terminal Output Samples

1. PWM_DynamicDutyCycle on ESP32_DEV

The following is the sample terminal output when running example PWM_DynamicDutyCycle on ESP32_DEV*, to demonstrate the ability to provide high PWM frequencies and ability to change DutyCycle on-the-fly.

Starting PWM_DynamicDutyCycle on ESP32_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 16 , LEDC_MAX_BIT_WIDTH = 20
[PWM] ESP32_FastPWM: _dutycycle = 32768
[PWM] setPWM_Int: _dutycycle = 128 , DC % = 50.00
=====================================================================================
Change PWM DutyCycle to 90.00
[PWM] setPWM: _dutycycle = 58982 , frequency = 5000.00
[PWM] setPWM_Int: _dutycycle = 230 , DC % = 89.84
=====================================================================================
Actual data: pin = 16, PWM DC = 89.84, PWMPeriod = 200.00, PWM Freq (Hz) = 5000.0000
=====================================================================================
Change PWM DutyCycle to 20.00
[PWM] setPWM: _dutycycle = 13107 , frequency = 5000.00
[PWM] setPWM_Int: _dutycycle = 51 , DC % = 19.92
=====================================================================================
Actual data: pin = 16, PWM DC = 19.92, PWMPeriod = 200.00, PWM Freq (Hz) = 5000.0000
=====================================================================================
Change PWM DutyCycle to 90.00
[PWM] setPWM: _dutycycle = 58982 , frequency = 5000.00
[PWM] setPWM_Int: _dutycycle = 230 , DC % = 89.84
=====================================================================================
Actual data: pin = 16, PWM DC = 89.84, PWMPeriod = 200.00, PWM Freq (Hz) = 5000.0000
=====================================================================================

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2. PWM_Multi on ESP32_DEV

The following is the sample terminal output when running example PWM_Multi on ESP32_DEV, to demonstrate the ability to provide high PWM frequencies on multiple PWM-capable pins.

Starting PWM_Multi on ESP32_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: new _channel = 0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 16 , LEDC_MAX_BIT_WIDTH = 20
[PWM] ESP32_FastPWM: _dutycycle = 6553
[PWM] setPWM_Int: _dutycycle = 409 , DC % = 9.99
[PWM] ESP32_FastPWM: new _channel = 2
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 16 , LEDC_MAX_BIT_WIDTH = 20
[PWM] ESP32_FastPWM: _dutycycle = 19660
[PWM] setPWM_Int: _dutycycle = 1228 , DC % = 29.98
[PWM] ESP32_FastPWM: new _channel = 4
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 16 , LEDC_MAX_BIT_WIDTH = 20
[PWM] ESP32_FastPWM: _dutycycle = 32768
[PWM] setPWM_Int: _dutycycle = 2048 , DC % = 50.00
[PWM] ESP32_FastPWM: new _channel = 6
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 16 , LEDC_MAX_BIT_WIDTH = 20
[PWM] ESP32_FastPWM: _dutycycle = 58982
[PWM] setPWM_Int: _dutycycle = 3686 , DC % = 89.99
=====================================================================================
Index	Pin	PWM_freq	DutyCycle	Actual Freq
=====================================================================================
0	25	2000.00		10.00		2000.0000
1	27	3000.00		30.00		3000.0000
2	21	4000.00		50.00		4000.0000
3	22	8000.00		90.00		8000.0000
=====================================================================================
Actual data: pin = 16, PWM DC = 9.99, PWMPeriod = 500.00, PWM Freq (Hz) = 2000.0000
=====================================================================================
=====================================================================================
Actual data: pin = 17, PWM DC = 29.98, PWMPeriod = 333.33, PWM Freq (Hz) = 3000.0000
=====================================================================================
=====================================================================================
Actual data: pin = 19, PWM DC = 50.00, PWMPeriod = 250.00, PWM Freq (Hz) = 4000.0000
=====================================================================================
=====================================================================================
Actual data: pin = 21, PWM DC = 89.99, PWMPeriod = 125.00, PWM Freq (Hz) = 8000.0000
=====================================================================================

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3. PWM_DynamicFreq on ESP32S3_DEV

The following is the sample terminal output when running example PWM_DynamicFreq on ESP32S3_DEV, to demonstrate the ability to change dynamically PWM frequencies.

Starting PWM_DynamicFreq on ESP32S3_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 8 , LEDC_MAX_BIT_WIDTH = 14
[PWM] ESP32_FastPWM: _dutycycle = 32768
[PWM] setPWM_Int: _dutycycle = 128 , DC % = 50.00
=====================================================================================
Change PWM Freq to 20000.00
[PWM] setPWM: _dutycycle = 32768 , frequency = 20000.00
[PWM] setPWM_Int: _dutycycle = 128 , DC % = 50.00
[PWM] setPWM_Int: change frequency to 20000.00 from 10000.00
=====================================================================================
Actual data: pin = 16, PWM DC = 50.00, PWMPeriod = 50.00, PWM Freq (Hz) = 20000.0000
=====================================================================================
Change PWM Freq to 10000.00
[PWM] setPWM: _dutycycle = 32768 , frequency = 10000.00
[PWM] setPWM_Int: _dutycycle = 128 , DC % = 50.00
[PWM] setPWM_Int: change frequency to 10000.00 from 20000.00
=====================================================================================
Actual data: pin = 16, PWM DC = 50.00, PWMPeriod = 100.00, PWM Freq (Hz) = 10000.0000
=====================================================================================
Change PWM Freq to 20000.00
[PWM] setPWM: _dutycycle = 32768 , frequency = 20000.00
[PWM] setPWM_Int: _dutycycle = 128 , DC % = 50.00
[PWM] setPWM_Int: change frequency to 20000.00 from 10000.00
=====================================================================================
Actual data: pin = 16, PWM DC = 50.00, PWMPeriod = 50.00, PWM Freq (Hz) = 20000.0000
=====================================================================================
Change PWM Freq to 10000.00
[PWM] setPWM: _dutycycle = 32768 , frequency = 10000.00
[PWM] setPWM_Int: _dutycycle = 128 , DC % = 50.00
[PWM] setPWM_Int: change frequency to 10000.00 from 20000.00
=====================================================================================
Actual data: pin = 16, PWM DC = 50.00, PWMPeriod = 100.00, PWM Freq (Hz) = 10000.0000
=====================================================================================

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4. PWM_Waveform on ESP32S2_DEV

The following is the sample terminal output when running example PWM_Waveform on ESP32S2_DEV, to demonstrate how to use the setPWM_manual() function in wafeform creation

Starting PWM_Waveform on ESP32S2_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: new _channel = 0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 8 , LEDC_MAX_BIT_WIDTH = 14
[PWM] ESP32_FastPWM: _dutycycle = 0
[PWM] setPWM: _dutycycle = 0 , frequency = 1000.00
[PWM] setPWM_Int: _dutycycle = 0 , DC % = 0.00
============================================================================================
Actual data: pin = 16, PWM DutyCycle = 0.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
============================================================================================
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 204 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 409 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 614 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 819 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1024 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1228 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1433 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1638 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1843 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2048 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2252 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2457 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2662 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2867 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3072 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3481 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3686 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3891 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 4096 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3891 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3686 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3481 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3072 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2867 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2662 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2457 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2252 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2048 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1843 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1638 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1433 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1228 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1024 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 819 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 614 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 409 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 204 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00

---

5. PWM_Waveform on ESP32C3_DEV

The following is the sample terminal output when running example PWM_Waveform on ESP32C3_DEV, to demonstrate how to use the setPWM_manual() function in wafeform creation

Starting PWM_Waveform on ESP32C3_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: new _channel = 0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 6 , LEDC_CHANNELS = 6 , LEDC_MAX_BIT_WIDTH = 14
[PWM] ESP32_FastPWM: _dutycycle = 0
[PWM] setPWM: _dutycycle = 0 , frequency = 1000.00
[PWM] setPWM_Int: _dutycycle = 0 , DC % = 0.00
============================================================================================
Actual data: pin = 9, PWM DutyCycle = 0.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
============================================================================================
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 204 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 409 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 614 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 819 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1024 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1228 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1433 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1638 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1843 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2048 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2252 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2457 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2662 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2867 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3072 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3481 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3686 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3891 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 4096 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3891 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3686 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3481 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3072 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2867 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2662 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2457 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2252 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2048 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1843 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1638 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1433 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1228 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1024 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 819 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 614 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 409 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 204 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00

---

6. PWM_Waveform on ESP32S3_DEV

The following is the sample terminal output when running example PWM_Waveform on ESP32S3_DEV, to demonstrate how to use the setPWM_manual() function in wafeform creation

Starting PWM_Waveform on ESP32S3_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: new _channel = 0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 8 , LEDC_MAX_BIT_WIDTH = 14
[PWM] ESP32_FastPWM: _dutycycle = 0
[PWM] setPWM: _dutycycle = 0 , frequency = 1000.00
[PWM] setPWM_Int: _dutycycle = 0 , DC % = 0.00
============================================================================================
Actual data: pin = 16, PWM DutyCycle = 0.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
============================================================================================
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 204 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 409 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 614 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 819 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1024 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1228 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1433 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1638 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1843 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2048 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2252 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2457 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2662 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2867 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3072 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3481 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3686 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3891 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 4096 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3891 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3686 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3481 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 3072 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2867 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2662 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2457 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2252 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 2048 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1843 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1638 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1433 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1228 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 1024 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 819 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 614 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 409 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 204 , _frequency = 1000.00
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00

---

7. PWM_manual on ESP32_DEV

The following is the sample terminal output when running example PWM_manual on ESP32_DEV, to demonstrate how to use the setPWM_manual() and setPWM_DCPercentage_manual() functions in wafeform creation

Starting PWM_manual on ESP32_DEV
ESP32_FastPWM v1.1.0
[PWM] ESP32_FastPWM: new _channel = 0
[PWM] ESP32_FastPWM: SOC_LEDC_CHANNEL_NUM = 8 , LEDC_CHANNELS = 16 , LEDC_MAX_BIT_WIDTH = 20
[PWM] ESP32_FastPWM: _dutycycle = 0
[PWM] setPWM_Int: _dutycycle = 0 , DC % = 0.00
=================================================================================================
Actual data: pin = 16, PWM DC = 0.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 0.00 , new_dc = 0
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 0.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 5.00 , new_dc = 3276
[PWM] setPWM_manual: DCValue = 3276 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 5.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 10.00 , new_dc = 6553
[PWM] setPWM_manual: DCValue = 6553 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 10.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 15.00 , new_dc = 9830
[PWM] setPWM_manual: DCValue = 9830 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 15.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 20.00 , new_dc = 13107
[PWM] setPWM_manual: DCValue = 13107 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 20.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 25.00 , new_dc = 16384
[PWM] setPWM_manual: DCValue = 16384 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 25.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 30.00 , new_dc = 19660
[PWM] setPWM_manual: DCValue = 19660 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 30.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 35.00 , new_dc = 22937
[PWM] setPWM_manual: DCValue = 22937 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 35.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 40.00 , new_dc = 26214
[PWM] setPWM_manual: DCValue = 26214 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 40.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 45.00 , new_dc = 29491
[PWM] setPWM_manual: DCValue = 29491 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 45.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 50.00 , new_dc = 32768
[PWM] setPWM_manual: DCValue = 32768 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 50.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 55.00 , new_dc = 36044
[PWM] setPWM_manual: DCValue = 36044 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 55.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 60.00 , new_dc = 39321
[PWM] setPWM_manual: DCValue = 39321 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 60.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 65.00 , new_dc = 42598
[PWM] setPWM_manual: DCValue = 42598 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 65.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 70.00 , new_dc = 45875
[PWM] setPWM_manual: DCValue = 45875 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 70.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 75.00 , new_dc = 49152
[PWM] setPWM_manual: DCValue = 49152 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 75.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 80.00 , new_dc = 52428
[PWM] setPWM_manual: DCValue = 52428 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 80.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 85.00 , new_dc = 55705
[PWM] setPWM_manual: DCValue = 55705 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 85.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 90.00 , new_dc = 58982
[PWM] setPWM_manual: DCValue = 58982 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 90.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 95.00 , new_dc = 62259
[PWM] setPWM_manual: DCValue = 62259 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 95.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================
[PWM] setPWM_DCPercentage_manual: DCPercentage = 100.00 , new_dc = 0
[PWM] setPWM_manual: DCValue = 0 , _frequency = 1000.00
=================================================================================================
Actual data: pin = 16, PWM DC = 0.00, PWMPeriod = 1000.00, PWM Freq (Hz) = 1000.0000
=================================================================================================

---

---

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 "ESP32_FastPWM.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: ESP32_FastPWM issues

---

TO DO

1. Search for bug and improvement.

---

DONE

1. Basic hardware PWM-channels for ESP32, ESP32_S2, ESP32_S3 and ESP32_C3 using ESP32 core
2. Add example PWM_StepperControl to demo how to control Stepper Motor using PWM
3. Add example PWM_manual to demo how to correctly use PWM to generate waveform
4. Add function setPWM_DCPercentage_manual() to facilitate the setting PWM DC manually by using DCPercentage, instead of absolute DCValue depending on varying PWMPeriod
5. Fix glitch when changing PWM frequency

---

---

Contributions and Thanks

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

1. Thanks to Paul van Dinther for proposing new way to use PWM to drive Stepper-Motor in Using PWM to step a stepper driver #16, leading to v1.0.1

Paul van Dinther

---

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

---

Copyright

Copyright (c) 2022- Khoi Hoang