khoih-prog / nrf52_pwm

This library enables you to use Hardware-based PWM channels on nRF52-based boards to create and output PWM to pins. Using the same functions as other FastPWM libraries to enable you to port PWM code easily between platforms.

nRF52_PWM Library

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Table of Contents

• Why do we need this nRF52_PWM library
  • Features
  • Why using hardware-based PWM is better
  • Currently supported Boards
• Changelog
• Prerequisites
• Installation
  • Use Arduino Library Manager
  • Manual Install
  • VS Code & PlatformIO
• Packages' Patches
  • 1. For Adafruit nRF52840 and nRF52832 boards
  • 2. For Seeeduino nRF52840 boards
• Usage
  • 1. Create PWM Instance with Pin, Frequency, dutycycle
  • 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
• Example PWM_Multi
• Debug Terminal Output Samples
  • 1. PWM_DynamicDutyCycle on NRF52840_FEATHER
  • 2. PWM_Multi on NRF52840_FEATHER
  • 3. PWM_DynamicFreq on NRF52840_FEATHER
  • 4. PWM_Waveform on NRF52840_FEATHER
  • 5. PWM_Waveform on NRF52840_ITSYBITSY
• Debug
• Troubleshooting
• Issues
• TO DO
• DONE
• Contributions and Thanks
• Contributing
• License
• Copyright

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Why do we need this nRF52_PWM library

Features

This hardware-based PWM library enables you to use Hardware-PWM on nRF52-based boards, such as AdaFruit Itsy-Bitsy nRF52840, Feather nRF52840 Express, Seeed XIAO nRF52840, Seeed XIAO nRF52840 Sense, 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 and default resolution is 16-bit resolution.

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() function enables waveform creation using PWM.

The PWM_Multi example will demonstrate the usage of multichannel PWM using multiple Hardware-PWM blocks (Timer & Channel). The 4 independent Hardware-PWM channels are used to control 4 different PWM outputs, with totally independent frequencies and dutycycles on nRF52.

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.

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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. AdaFruit Feather nRF52832, nRF52840 Express, BlueFruit Sense, Itsy-Bitsy nRF52840 Express, Metro nRF52840 Express, NINA_B302_ublox, NINA_B112_ublox etc.
2. Sparkfun Pro nRF52840 Mini
3. Seeeduino nRF52840-based boards such as SEEED_XIAO_NRF52840 and SEEED_XIAO_NRF52840_SENSE, etc. using Seeeduino nRF52 core

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Prerequisites

1. Arduino IDE 1.8.19+ for Arduino.
2. Adafruit nRF52 v1.3.0+ for nRF52 boards such as Adafruit NRF52840_FEATHER, NRF52832_FEATHER, NRF52840_FEATHER_SENSE, NRF52840_ITSYBITSY, NRF52840_CIRCUITPLAY, NRF52840_CLUE, NRF52840_METRO, NRF52840_PCA10056, PARTICLE_XENON, NINA_B302_ublox, etc.
3. Seeeduino nRF52 core 1.1.0+ for Seeeduino nRF52840-based boards such as Seeed_XIAO_NRF52840 and Seeed_XIAO_NRF52840_SENSE.

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Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for nRF52_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:

1. Navigate to nRF52_PWM page.
2. Download the latest release nRF52_PWM-main.zip.
3. Extract the zip file to nRF52_PWM-main directory
4. Copy whole nRF52_PWM-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO

1. Install VS Code
2. Install PlatformIO
3. Install nRF52_PWM library by using Library Manager. Search for nRF52_PWM 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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Packages' Patches

1. For Adafruit nRF52840 and nRF52832 boards

To be able to compile, run and automatically detect and display BOARD_NAME on nRF52840/nRF52832 boards, you have to copy the whole nRF52 1.3.0 directory into Adafruit nRF52 directory (~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0).

Supposing the Adafruit nRF52 version is 1.3.0. These files must be copied into the directory:

• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/platform.txt
• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/boards.txt
• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/variants/NINA_B302_ublox/variant.h
• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/variants/NINA_B302_ublox/variant.cpp
• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/variants/NINA_B112_ublox/variant.h
• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/variants/NINA_B112_ublox/variant.cpp
• ~/.arduino15/packages/adafruit/hardware/nrf52/1.3.0/cores/nRF5/Udp.h

Whenever a new version is installed, remember to copy these files into the new version directory. For example, new version is x.yy.z These files must be copied into the directory:

• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/platform.txt
• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/boards.txt
• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/variants/NINA_B302_ublox/variant.h
• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/variants/NINA_B302_ublox/variant.cpp
• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/variants/NINA_B112_ublox/variant.h
• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/variants/NINA_B112_ublox/variant.cpp
• ~/.arduino15/packages/adafruit/hardware/nrf52/x.yy.z/cores/nRF5/Udp.h

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2. For Seeeduino nRF52840 boards

To be able to compile and run on Xiao nRF52840 boards, you have to copy the whole nRF52 1.0.0 directory into Seeeduino nRF52 directory (~/.arduino15/packages/Seeeduino/hardware/nrf52/1.0.0).

Supposing the Seeeduino nRF52 version is 1.0.0. These files must be copied into the directory:

• ~/.arduino15/packages/Seeeduino/hardware/nrf52/1.0.0/cores/nRF5/Print.h
• ~/.arduino15/packages/Seeeduino/hardware/nrf52/1.0.0/cores/nRF5/Print.cpp
• ~/.arduino15/packages/Seeeduino/hardware/nrf52/1.0.0/cores/nRF5/Udp.h

Whenever a new version is installed, remember to copy these files into the new version directory. For example, new version is x.yy.z These files must be copied into the directory:

• ~/.arduino15/packages/Seeeduino/hardware/nrf52/x.yy.z/cores/nRF5/Print.h
• ~/.arduino15/packages/Seeeduino/hardware/nrf52/x.yy.z/cores/nRF5/Print.cpp
• ~/.arduino15/packages/Seeeduino/hardware/nrf52/x.yy.z/cores/nRF5/Udp.h

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To use Sparkfun Pro nRF52840 Mini, you must install Packages_Patches and use Adafruit nrf52 core v1.0.0+

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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.

// OK for Feather_nRF52840_Express   (5, 6, 9-13, 14-21/A0-A7, etc.)
// OK for ItsyBitsy_nRF52840_Express (5, 7, 9-13, 14-20/A0-A6, etc.)

1. Create PWM Instance with Pin, Frequency, dutycycle

nRF52_PWM* PWM_Instance;

PWM_Instance = new nRF52_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);

Need to call only once for each pin

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

after that, if just changing dutyCycle / level, use

PWM_Instance->setPWM_manual(PWM_Pins, new_level);

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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

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Example PWM_Multi

nRF52_PWM/examples/PWM_Multi/PWM_Multi.ino

Lines 1 to 102 in 2384153

	/****************************************************************************************************************************
	PWM_Multi.ino
	For nRF52-based boards usinghardware-based PWM with Adafruit_nRF52_Arduino core
	Written by Khoi Hoang
	Built by Khoi Hoang https://github.com/khoih-prog/nRF52_PWM
	Licensed under MIT license
	*****************************************************************************************************************************/
	#define _PWM_LOGLEVEL_ 4
	// Select false to use PWM
	#define USING_TIMER false //true
	#include "nRF52_PWM.h"
	// OK for Feather_nRF52840_Express (5, 6, 9-13, 14-21/A0-A7, etc.)
	// OK for ItsyBitsy_nRF52840_Express (5, 7, 9-13, 14-20/A0-A6, etc.)
	// To select correct pins for different frequencies
	uint32_t PWM_Pins[] = { 5, 7, 9, 10 };
	float frequency[] = { 2000.0f, 3000.0f, 4000.0f, 8000.0f };
	float dutyCycle[] = { 10.0f, 30.0f, 50.0f, 90.0f };
	#define NUM_OF_PINS ( sizeof(PWM_Pins) / sizeof(uint32_t) )
	nRF52_PWM* PWM_Instance[NUM_OF_PINS];
	char dashLine[] = "=====================================================================================";
	void printPWMInfo(nRF52_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(BOARD_NAME);
	Serial.println(NRF52_PWM_VERSION);
	for (uint8_t index = 0; index < NUM_OF_PINS; index++)
	{
	PWM_Instance[index] = new nRF52_PWM(PWM_Pins[index], frequency[index], dutyCycle[index]);
	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 NRF52840_FEATHER

The following is the sample terminal output when running example PWM_DynamicDutyCycle on NRF52840_FEATHER, to demonstrate the ability to provide high PWM frequencies and ability to change DutyCycle on-the-fly

Starting PWM_DynamicDutyCycle on NRF52840_FEATHER
nRF52_PWM v1.0.1
[PWM] nRF52_PWM: NRF52_PWM_TOKEN = 0x345CD8
[PWM] calcPrescaler: OK  period = 200 , _prescaler = 1 , countTOP = 3200
[PWM] calcPrescaler: _dutycycle = 0 , frequency = 5000.00 , _prescalerConfigBits = 0 , _compareValue = 3199
[PWM] setupPWM: pin = 6 assigned to new PWM module = 0
[PWM] setupPWM: dutycycle = 0 , frequency = 5000 , _resolution = 15
=====================================================================================
Change PWM DutyCycle to 90.00
[PWM] setPWM: _dutycycle = 58982 , frequency = 5000.00
[PWM] setPWM_Int: dutycycle = 58982 , frequency = 5000.00
[PWM] setupPWM: Same _pin = 6 to PWM module = 0 , ch = 0
[PWM] setupPWM: dutycycle = 29491 , frequency = 5000 , _resolution = 15
=====================================================================================
Actual data: pin = 6, PWM DC = 90.00, 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 = 13107 , frequency = 5000.00
[PWM] setupPWM: Same _pin = 6 to PWM module = 0 , ch = 0
[PWM] setupPWM: dutycycle = 6553 , frequency = 5000 , _resolution = 15
=====================================================================================
Actual data: pin = 6, PWM DC = 20.00, 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 = 58982 , frequency = 5000.00
[PWM] setupPWM: Same _pin = 6 to PWM module = 0 , ch = 0
[PWM] setupPWM: dutycycle = 29491 , frequency = 5000 , _resolution = 15
=====================================================================================
Actual data: pin = 6, PWM DC = 90.00, PWMPeriod = 200.00, PWM Freq (Hz) = 5000.0000
=====================================================================================

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2. PWM_Multi on NRF52840_FEATHER

The following is the sample terminal output when running example PWM_Multi on NRF52840_FEATHER, to demonstrate the ability to provide high PWM frequencies on multiple PWM-capable pins

Starting PWM_Multi on NRF52840_FEATHER
nRF52_PWM v1.0.1
[PWM] nRF52_PWM: NRF52_PWM_TOKEN = 0x389838
[PWM] calcPrescaler: OK  period = 500 , _prescaler = 1 , countTOP = 8000
[PWM] calcPrescaler: _dutycycle = 6553 , frequency = 2000.00 , _prescalerConfigBits = 0 , _compareValue = 7999
[PWM] setupPWM: pin = 5 assigned to new PWM module = 0
[PWM] setupPWM: dutycycle = 3276 , frequency = 2000 , _resolution = 15
[PWM] setPWM_Int: dutycycle = 6553 , frequency = 2000.00
[PWM] setupPWM: Same _pin = 5 to PWM module = 0 , ch = 0
[PWM] setupPWM: dutycycle = 3276 , frequency = 2000 , _resolution = 15
[PWM] nRF52_PWM: NRF52_PWM_TOKEN = 0x389FD9
[PWM] calcPrescaler: OK  period = 333 , _prescaler = 1 , countTOP = 5333
[PWM] calcPrescaler: _dutycycle = 19660 , frequency = 3000.00 , _prescalerConfigBits = 0 , _compareValue = 5332
[PWM] setupPWM: pin = 6 assigned to new PWM module = 1
[PWM] setupPWM: dutycycle = 9830 , frequency = 3000 , _resolution = 15
[PWM] setPWM_Int: dutycycle = 19660 , frequency = 3000.00
[PWM] setupPWM: Same _pin = 6 to PWM module = 1 , ch = 0
[PWM] setupPWM: dutycycle = 9830 , frequency = 3000 , _resolution = 15
[PWM] nRF52_PWM: NRF52_PWM_TOKEN = 0x38A77A
[PWM] calcPrescaler: OK  period = 250 , _prescaler = 1 , countTOP = 4000
[PWM] calcPrescaler: _dutycycle = 32768 , frequency = 4000.00 , _prescalerConfigBits = 0 , _compareValue = 3999
[PWM] setupPWM: pin = 9 assigned to new PWM module = 2
[PWM] setupPWM: dutycycle = 16384 , frequency = 4000 , _resolution = 15
[PWM] setPWM_Int: dutycycle = 32768 , frequency = 4000.00
[PWM] setupPWM: Same _pin = 9 to PWM module = 2 , ch = 0
[PWM] setupPWM: dutycycle = 16384 , frequency = 4000 , _resolution = 15
[PWM] nRF52_PWM: NRF52_PWM_TOKEN = 0x38B2EC
[PWM] calcPrescaler: OK  period = 125 , _prescaler = 1 , countTOP = 2000
[PWM] calcPrescaler: _dutycycle = 58982 , frequency = 8000.00 , _prescalerConfigBits = 0 , _compareValue = 1999
[PWM] setupPWM: pin = 10 assigned to new PWM module = 3
[PWM] setupPWM: dutycycle = 29491 , frequency = 8000 , _resolution = 15
[PWM] setPWM_Int: dutycycle = 58982 , frequency = 8000.00
[PWM] setupPWM: Same _pin = 10 to PWM module = 3 , ch = 0
[PWM] setupPWM: dutycycle = 29491 , frequency = 8000 , _resolution = 15
=====================================================================================
Index	Pin	PWM_freq	DutyCycle	Actual Freq
=====================================================================================
0	5	2000.00		10.00		2000.0000
1	6	3000.00		30.00		3000.0000
2	9	4000.00		50.00		4000.0000
3	10	8000.00		90.00		8000.0000
=====================================================================================
Actual data: pin = 5, PWM DC = 10.00, PWMPeriod = 500.00, PWM Freq (Hz) = 2000.0000
=====================================================================================
=====================================================================================
Actual data: pin = 6, PWM DC = 30.00, PWMPeriod = 333.33, PWM Freq (Hz) = 3000.0000
=====================================================================================
=====================================================================================
Actual data: pin = 9, PWM DC = 50.00, PWMPeriod = 250.00, PWM Freq (Hz) = 4000.0000
=====================================================================================
=====================================================================================
Actual data: pin = 10, PWM DC = 90.00, PWMPeriod = 125.00, PWM Freq (Hz) = 8000.0000
=====================================================================================

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3. PWM_DynamicFreq on NRF52840_FEATHER

The following is the sample terminal output when running example PWM_DynamicFreq on NRF52840_FEATHER, to demonstrate the ability to change dynamically PWM frequencies

Starting PWM_DynamicFreq on NRF52840_FEATHER
nRF52_PWM v1.0.1
[PWM] nRF52_PWM: NRF52_PWM_TOKEN = 0x2B8A8B
[PWM] calcPrescaler: OK  period = 100 , _prescaler = 1 , countTOP = 1600
[PWM] calcPrescaler: _dutycycle = 32768 , frequency = 10000.00 , _prescalerConfigBits = 0 , _compareValue = 1599
[PWM] setupPWM: pin = 6 assigned to new PWM module = 0
[PWM] setupPWM: dutycycle = 16384 , frequency = 10000 , _resolution = 15
=====================================================================================
Change PWM Freq to 20000.00
[PWM] setPWM: _dutycycle = 32768 , frequency = 20000.00
[PWM] setPWM_Int: dutycycle = 32768 , frequency = 20000.00
[PWM] calcPrescaler: OK  period = 50 , _prescaler = 1 , countTOP = 800
[PWM] calcPrescaler: _dutycycle = 32768 , frequency = 20000.00 , _prescalerConfigBits = 0 , _compareValue = 799
[PWM] setupPWM: Same _pin = 6 to PWM module = 0 , ch = 0
[PWM] setupPWM: dutycycle = 16384 , frequency = 20000 , _resolution = 15
=====================================================================================
Actual data: pin = 6, 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 = 32768 , frequency = 10000.00
[PWM] calcPrescaler: OK  period = 100 , _prescaler = 1 , countTOP = 1600
[PWM] calcPrescaler: _dutycycle = 32768 , frequency = 10000.00 , _prescalerConfigBits = 0 , _compareValue = 1599
[PWM] setupPWM: Same _pin = 6 to PWM module = 0 , ch = 0
[PWM] setupPWM: dutycycle = 16384 , frequency = 10000 , _resolution = 15
=====================================================================================
Actual data: pin = 6, PWM DC = 50.00, PWMPeriod = 100.00, PWM Freq (Hz) = 10000.0000
=====================================================================================

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4. PWM_Waveform on NRF52840_FEATHER

The following is the sample terminal output when running example PWM_Waveform on NRF52840_FEATHER, to demonstrate how to use the setPWM_manual() function in wafeform creation

Starting PWM_Waveform on NRF52840_FEATHER
nRF52_PWM v1.0.1
[PWM] setPWM_Int: dutycycle = 0 , frequency = 2000.00
============================================================================================
Actual data: pin = 6, PWM DutyCycle = 0.00, PWMPeriod = 500.00, PWM Freq (Hz) = 2000.0000
============================================================================================
[PWM] setPWM_manual: _dutycycle = 0 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 3276 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 6553 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 9830 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 13107 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 16383 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 19660 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 22937 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 26214 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 29490 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 32767 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 36044 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 39321 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 42597 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 45874 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 49151 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 52428 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 55704 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 58981 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 62258 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 65535 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 62258 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 58981 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 55704 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 52428 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 49151 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 45874 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 42597 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 39321 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 36044 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 32767 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 29490 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 26214 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 22937 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 19660 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 16383 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 13107 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 9830 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 6553 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 3276 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 0 , frequency = 2000.00

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5. PWM_Waveform on NRF52840_ITSYBITSY

The following is the sample terminal output when running example PWM_Waveform on NRF52840_ITSYBITSY, to demonstrate how to use the setPWM_manual() function in wafeform creation

Starting PWM_Waveform on NRF52840_ITSYBITSY
nRF52_PWM v1.0.1
[PWM] setPWM_Int: dutycycle = 0 , frequency = 2000.00
============================================================================================
Actual data: pin = 7, PWM DutyCycle = 0.00, PWMPeriod = 500.00, PWM Freq (Hz) = 2000.0000
============================================================================================
[PWM] setPWM_manual: _dutycycle = 0 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 3276 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 6553 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 9830 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 13107 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 16383 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 19660 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 22937 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 26214 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 29490 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 32767 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 36044 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 39321 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 42597 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 45874 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 49151 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 52428 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 55704 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 58981 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 62258 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 65535 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 62258 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 58981 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 55704 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 52428 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 49151 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 45874 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 42597 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 39321 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 36044 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 32767 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 29490 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 26214 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 22937 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 19660 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 16383 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 13107 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 9830 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 6553 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 3276 , frequency = 2000.00
[PWM] setPWM_manual: _dutycycle = 0 , frequency = 2000.00

---

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Debug

Debug is enabled by default on Serial.

You can also change the debugging level _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_     0

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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.

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Issues

Submit issues to: nRF52_PWM issues

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TO DO

1. Search for bug and improvement.
2. Similar features for remaining Arduino boards

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DONE

1. Basic hardware PWM-channels for nRF52-based boards, such as AdaFruit Itsy-Bitsy nRF52840, Feather nRF52840 Express, Seeed XIAO nRF52840, Seeed XIAO nRF52840 Sense, etc. using

• Adafruit nRF52 core or
• Seeeduino nRF52 core

2. Add example PWM_StepperControl to demo how to control Stepper Motor using PWM

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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 v2.0.3

Paul van Dinther

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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

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License

• The library is licensed under MIT

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Copyright

Copyright (c) 2022- Khoi Hoang