diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 0560abc..69444dd 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -26,11 +26,10 @@ Please ensure to specify the following:
 ### Example
 
 ```
-Arduino IDE version: 1.8.13
+Arduino IDE version: 1.8.16
 Arduino SAMDUE Core Version 1.6.12
 OS: Ubuntu 20.04 LTS
-Linux xy-Inspiron-3593 5.4.0-86-generic #97-Ubuntu SMP Fri Sep 17 19:19:40 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
-
+Linux xy-Inspiron-3593 5.4.0-90-generic #101-Ubuntu SMP Fri Oct 15 20:00:55 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
 Context:
 I encountered a crash while trying to use the Timer Interrupt.
 
diff --git a/README.md b/README.md
index c5aec01..2388799 100644
--- a/README.md
+++ b/README.md
@@ -27,14 +27,18 @@
   * [1. Init ISR_PWM](#1-init-ISR_PWM)
   * [2. Set PWM Frequency, dutycycle, attach irqCallbackStartFunc and irqCallbackStopFunc functions](#2-Set-PWM-Frequency-dutycycle-attach-irqCallbackStartFunc-and-irqCallbackStopFunc-functions)
 * [Examples](#examples)
-  * [  1. ISR_8_PWMs_Array](examples/ISR_8_PWMs_Array)
-  * [  2. ISR_8_PWMs_Array_Complex](examples/ISR_8_PWMs_Array_Complex)
-  * [  3. ISR_8_PWMs_Array_Simple](examples/ISR_8_PWMs_Array_Simple)
+  * [ 1. ISR_8_PWMs_Array](examples/ISR_8_PWMs_Array)
+  * [ 2. ISR_8_PWMs_Array_Complex](examples/ISR_8_PWMs_Array_Complex)
+  * [ 3. ISR_8_PWMs_Array_Simple](examples/ISR_8_PWMs_Array_Simple)
+  * [ 4. ISR_Changing_PWM](examples/ISR_Changing_PWM)
+  * [ 5. ISR_Modify_PWM](examples/ISR_Modify_PWM)
 * [Example ISR_8_PWMs_Array_Complex](#Example-ISR_8_PWMs_Array_Complex)
 * [Debug Terminal Output Samples](#debug-terminal-output-samples)
   * [1. ISR_8_PWMs_Array_Complex on SAM_DUE](#1-ISR_8_PWMs_Array_Complex-on-SAM_DUE)
   * [2. ISR_8_PWMs_Array on SAM_DUE](#2-isr_8_pwms_array-on-SAM_DUE)
   * [3. ISR_8_PWMs_Array_Simple on SAM_DUE](#3-ISR_8_PWMs_Array_Simple-on-SAM_DUE)
+  * [4. ISR_Modify_PWM on SAM_DUE](#4-ISR_Modify_PWM-on-SAM_DUE)
+  * [5. ISR_Changing_PWM on SAM_DUE](#5-ISR_Changing_PWM-on-SAM_DUE)
 * [Debug](#debug)
 * [Troubleshooting](#troubleshooting)
 * [Issues](#issues)
@@ -52,7 +56,7 @@
 
 ### Features
 
-This library enables you to use ISR-based PWM channels on **SAM_DUE** boards, using [`Arduino SAM core`](https://github.com/arduino/ArduinoCore-sam), to create and output PWM any GPIO pin. Because this library doesn't use the powerful purely hardware-controlled PWM with many limitations, the maximum PWM frequency is currently limited at **1000Hz**, which is still suitable for many real-life applications.
+This library enables you to use ISR-based PWM channels on **SAM_DUE** boards, using [`Arduino SAM core`](https://github.com/arduino/ArduinoCore-sam), to create and output PWM any GPIO pin. Because this library doesn't use the powerful purely hardware-controlled PWM with many limitations, the maximum PWM frequency is currently limited at **1000Hz**, which is still suitable for many real-life applications. Now you can also modify PWM settings on-the-fly.
 
 ---
 
@@ -97,7 +101,7 @@ The catch is **your function is now part of an ISR (Interrupt Service Routine),
 
 ### Currently supported Boards
 
-1. ****SAM_DUE** boards**, using [`Arduino SAM core`](https://github.com/arduino/ArduinoCore-sam)
+1. **SAM_DUE** boards**, using [`Arduino SAM core`](https://github.com/arduino/ArduinoCore-sam)
 
 ---
 
@@ -236,7 +240,9 @@ void setup()
 
  1. [ISR_8_PWMs_Array](examples/ISR_8_PWMs_Array)
  2. [ISR_8_PWMs_Array_Complex](examples/ISR_8_PWMs_Array_Complex)
- 3. [ISR_8_PWMs_Array_Simple](examples/ISR_8_PWMs_Array_Simple) 
+ 3. [ISR_8_PWMs_Array_Simple](examples/ISR_8_PWMs_Array_Simple)
+ 4. [ISR_Changing_PWM](examples/ISR_Changing_PWM)
+ 5. [ISR_Modify_PWM](examples/ISR_Modify_PWM)
 
  
 ---
@@ -355,11 +361,10 @@ volatile unsigned long previousMicrosStart [NUMBER_ISR_PWMS] = { 0, 0, 0, 0, 0,
 volatile unsigned long deltaMicrosStop     [NUMBER_ISR_PWMS] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 volatile unsigned long previousMicrosStop  [NUMBER_ISR_PWMS] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 
-
 // You can assign any interval for any timer here, in Hz
-uint32_t PWM_Freq[NUMBER_ISR_PWMS] =
+double PWM_Freq[NUMBER_ISR_PWMS] =
 {
-  1,  2,  3,  5,  10,  20,  30,  50
+  1.0f,  2.0f,  3.0f,  5.0f,  10.0f,  20.0f,  30.0f,  50.0f
 };
 
 // You can assign any duty-cycle for any PWM channel here, in %
@@ -678,8 +683,7 @@ The following is the sample terminal output when running example [ISR_8_PWMs_Arr
 
 ```
 Starting ISR_8_PWMs_Array_Complex on SAM_DUE
-SAMDUE_Slow_PWM v1.0.0
-CPU Frequency = 84 MHz
+SAMDUE_Slow_PWM v1.1.0
 Timer Frequency = 84 MHz
 [PWM] Using Timer( 0 ) = TC0
 [PWM] Channel = 0 , IRQ = TC0_IRQn
@@ -720,8 +724,7 @@ The following is the sample terminal output when running example [**ISR_8_PWMs_A
 
 ```
 Starting ISR_8_PWMs_Array on SAM_DUE
-SAMDUE_Slow_PWM v1.0.0
-CPU Frequency = 84 MHz
+SAMDUE_Slow_PWM v1.1.0
 Timer Frequency = 84 MHz
 [PWM] Using Timer( 0 ) = TC0
 [PWM] Channel = 0 , IRQ = TC0_IRQn
@@ -744,8 +747,7 @@ The following is the sample terminal output when running example [**ISR_8_PWMs_A
 
 ```
 Starting ISR_8_PWMs_Array_Simple on SAM_DUE
-SAMDUE_Slow_PWM v1.0.0
-CPU Frequency = 84 MHz
+SAMDUE_Slow_PWM v1.1.0
 Timer Frequency = 84 MHz
 [PWM] Using Timer( 0 ) = TC0
 [PWM] Channel = 0 , IRQ = TC0_IRQn
@@ -760,6 +762,58 @@ Channel : 6	Period : 33333		OnTime : 13333	Start_Time : 2009415
 Channel : 7	Period : 20000		OnTime : 9000	Start_Time : 2009415
 ```
 
+---
+
+### 4. ISR_Modify_PWM on SAM_DUE
+
+The following is the sample terminal output when running example [ISR_Modify_PWM](examples/ISR_Modify_PWM) on **SAM_DUE** to demonstrate how to modify PWM settings on-the-fly without deleting the PWM channel
+
+```
+Starting ISR_Modify_PWM on SAM_DUE
+SAMDUE_Slow_PWM v1.1.0
+CPU Frequency = 84 MHz
+Timer Frequency = 84 MHz
+[PWM] Using Timer( 0 ) = TC0
+[PWM] Channel = 0 , IRQ = TC0_IRQn
+ITimer attached to Timer(0)
+Using PWM Freq = 1.00, PWM DutyCycle = 10
+Channel : 0	Period : 1000000		OnTime : 100000	Start_Time : 2012463
+Channel : 0	Period : 500000		OnTime : 450000	Start_Time : 12019042
+Channel : 0	Period : 1000000		OnTime : 100000	Start_Time : 22020042
+Channel : 0	Period : 500000		OnTime : 450000	Start_Time : 32021042
+```
+
+---
+
+### 5. ISR_Changing_PWM on SAM_DUE
+
+The following is the sample terminal output when running example [ISR_Changing_PWM](examples/ISR_Changing_PWM) on **SAM_DUE** 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 SAM_DUE
+SAMDUE_Slow_PWM v1.1.0
+CPU Frequency = 84 MHz
+Timer Frequency = 84 MHz
+[PWM] Using Timer( 0 ) = TC0
+[PWM] Channel = 0 , IRQ = TC0_IRQn
+ITimer attached to Timer(0)
+Using PWM Freq = 1.00, PWM DutyCycle = 50
+Channel : 0	Period : 1000000		OnTime : 500000	Start_Time : 2012611
+Using PWM Freq = 2.00, PWM DutyCycle = 90
+Channel : 0	Period : 500000		OnTime : 450000	Start_Time : 12018520
+Using PWM Freq = 1.00, PWM DutyCycle = 50
+Channel : 0	Period : 1000000		OnTime : 500000	Start_Time : 22019530
+Using PWM Freq = 2.00, PWM DutyCycle = 90
+Channel : 0	Period : 500000		OnTime : 450000	Start_Time : 32020520
+Using PWM Freq = 1.00, PWM DutyCycle = 50
+Channel : 0	Period : 1000000		OnTime : 500000	Start_Time : 42021531
+Using PWM Freq = 2.00, PWM DutyCycle = 90
+Channel : 0	Period : 500000		OnTime : 450000	Start_Time : 52022520
+Using PWM Freq = 1.00, PWM DutyCycle = 50
+Channel : 0	Period : 1000000		OnTime : 500000	Start_Time : 62023531
+Using PWM Freq = 2.00, PWM DutyCycle = 90
+Channel : 0	Period : 500000		OnTime : 450000	Start_Time : 72024520
+```
 
 ---
 ---
@@ -804,6 +858,7 @@ Submit issues to: [SAMDUE_Slow_PWM issues](https://github.com/khoih-prog/SAMDUE_
 
 1. Basic hardware multi-channel PWM for **SAM_DUE**, etc. using [`Arduino SAM core`](https://github.com/arduino/ArduinoCore-sam)
 2. Add Table of Contents
+3. Add functions to modify PWM settings on-the-fly
 
 ---
 ---
diff --git a/changelog.md b/changelog.md
index 9472402..4819f3a 100644
--- a/changelog.md
+++ b/changelog.md
@@ -12,6 +12,7 @@
 ## Table of Contents
 
 * [Changelog](#changelog)
+  * [Releases v1.1.0](#releases-v110)
   * [Initial Releases v1.0.0](#Initial-Releases-v100)
 
 ---
@@ -19,6 +20,11 @@
 
 ## Changelog
 
+### Releases v1.1.0
+
+1. Add functions to modify PWM settings on-the-fly
+2. Add example to demo how to modify PWM settings on-the-fly
+
 ### Initial Releases v1.0.0
 
 1. Initial coding to support **SAM_DUE**, etc. using [`Arduino SAM core`](https://github.com/arduino/ArduinoCore-sam)
diff --git a/examples/ISR_8_PWMs_Array/ISR_8_PWMs_Array.ino b/examples/ISR_8_PWMs_Array/ISR_8_PWMs_Array.ino
index 5c61c14..6cde81d 100644
--- a/examples/ISR_8_PWMs_Array/ISR_8_PWMs_Array.ino
+++ b/examples/ISR_8_PWMs_Array/ISR_8_PWMs_Array.ino
@@ -11,12 +11,6 @@
   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.
-
-  Version: 1.0.0
-
-  Version Modified By   Date      Comments
-  ------- -----------  ---------- -----------
-  1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
 *****************************************************************************************************************************/
 
 #if !( defined(ARDUINO_SAM_DUE) || defined(__SAM3X8E__) )
@@ -26,9 +20,7 @@
 // These define's must be placed at the beginning before #include "ESP32_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_      3
-
-//#define USING_MICROS_RESOLUTION       true  //false 
+#define _PWM_LOGLEVEL_      4
 
 #include "SAMDUE_Slow_PWM.h"
 
@@ -87,11 +79,10 @@ uint32_t PWM_Pin[] =
 
 #define NUMBER_ISR_PWMS         ( sizeof(PWM_Pin) / sizeof(uint32_t) )
 
-
 // You can assign any interval for any timer here, in Hz
-uint32_t PWM_Freq[NUMBER_ISR_PWMS] =
+double PWM_Freq[NUMBER_ISR_PWMS] =
 {
-  1,  2,  3,  5,  10,  20,  30,  50
+  1.0f,  2.0f,  3.0f,  5.0f,  10.0f,  20.0f,  30.0f,  50.0f
 };
 
 // You can assign any duty-cycle for any PWM channel here, in %
diff --git a/examples/ISR_8_PWMs_Array_Complex/ISR_8_PWMs_Array_Complex.ino b/examples/ISR_8_PWMs_Array_Complex/ISR_8_PWMs_Array_Complex.ino
index 8233b59..e08a5d4 100644
--- a/examples/ISR_8_PWMs_Array_Complex/ISR_8_PWMs_Array_Complex.ino
+++ b/examples/ISR_8_PWMs_Array_Complex/ISR_8_PWMs_Array_Complex.ino
@@ -11,12 +11,6 @@
   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.
-
-  Version: 1.0.0
-
-  Version Modified By   Date      Comments
-  ------- -----------  ---------- -----------
-  1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
 *****************************************************************************************************************************/
 
 #if !( defined(ARDUINO_SAM_DUE) || defined(__SAM3X8E__) )
@@ -28,8 +22,6 @@
 // Don't define _PWM_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system.
 #define _PWM_LOGLEVEL_      3
 
-//#define USING_MICROS_RESOLUTION       true  //false 
-
 #include "SAMDUE_Slow_PWM.h"
 
 #include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer
@@ -129,11 +121,10 @@ volatile unsigned long previousMicrosStart [NUMBER_ISR_PWMS] = { 0, 0, 0, 0, 0,
 volatile unsigned long deltaMicrosStop     [NUMBER_ISR_PWMS] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 volatile unsigned long previousMicrosStop  [NUMBER_ISR_PWMS] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 
-
 // You can assign any interval for any timer here, in Hz
-uint32_t PWM_Freq[NUMBER_ISR_PWMS] =
+double PWM_Freq[NUMBER_ISR_PWMS] =
 {
-  1,  2,  3,  5,  10,  20,  30,  50
+  1.0f,  2.0f,  3.0f,  5.0f,  10.0f,  20.0f,  30.0f,  50.0f
 };
 
 // You can assign any duty-cycle for any PWM channel here, in %
diff --git a/examples/ISR_8_PWMs_Array_Simple/ISR_8_PWMs_Array_Simple.ino b/examples/ISR_8_PWMs_Array_Simple/ISR_8_PWMs_Array_Simple.ino
index fd3aec8..18638cf 100644
--- a/examples/ISR_8_PWMs_Array_Simple/ISR_8_PWMs_Array_Simple.ino
+++ b/examples/ISR_8_PWMs_Array_Simple/ISR_8_PWMs_Array_Simple.ino
@@ -11,12 +11,6 @@
   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.
-
-  Version: 1.0.0
-
-  Version Modified By   Date      Comments
-  ------- -----------  ---------- -----------
-  1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
 *****************************************************************************************************************************/
 
 #if !( defined(ARDUINO_SAM_DUE) || defined(__SAM3X8E__) )
@@ -28,8 +22,6 @@
 // Don't define _PWM_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system.
 #define _PWM_LOGLEVEL_      3
 
-//#define USING_MICROS_RESOLUTION       true  //false 
-
 #include "SAMDUE_Slow_PWM.h"
 
 #include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer
@@ -87,11 +79,10 @@ uint32_t PWM_Pin[] =
 
 #define NUMBER_ISR_PWMS         ( sizeof(PWM_Pin) / sizeof(uint32_t) )
 
-
 // You can assign any interval for any timer here, in Hz
-uint32_t PWM_Freq[NUMBER_ISR_PWMS] =
+double PWM_Freq[NUMBER_ISR_PWMS] =
 {
-  1,  2,  3,  5,  10,  20,  30,  50
+  1.0f,  2.0f,  3.0f,  5.0f,  10.0f,  20.0f,  30.0f,  50.0f
 };
 
 // You can assign any duty-cycle for any PWM channel here, in %
diff --git a/examples/ISR_Changing_PWM/ISR_Changing_PWM.ino b/examples/ISR_Changing_PWM/ISR_Changing_PWM.ino
new file mode 100644
index 0000000..2fe8c6c
--- /dev/null
+++ b/examples/ISR_Changing_PWM/ISR_Changing_PWM.ino
@@ -0,0 +1,149 @@
+/****************************************************************************************************************************
+  ISR_Changing_PWM.ino
+  For Arduino SAM_DUE boards
+  Written by Khoi Hoang
+
+  Built by Khoi Hoang https://github.com/khoih-prog/SAMDUE_Slow_PWM
+  Licensed under MIT license
+  
+  Now even you use all these new 16 ISR-based timers,with their maximum interval practically unlimited (limited only by
+  unsigned long miliseconds), you just consume only one megaAVR-based timer and avoid conflicting with other cores' tasks.
+  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.
+*****************************************************************************************************************************/
+
+#if !( defined(ARDUINO_SAM_DUE) || defined(__SAM3X8E__) )
+  #error This is designed only for Arduino SAM_DUE board! Please check your Tools->Board setting.
+#endif
+
+// These define's must be placed at the beginning before #include "ESP32_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_      3
+
+#include "SAMDUE_Slow_PWM.h"
+
+#define LED_OFF             HIGH
+#define LED_ON              LOW
+
+#ifndef LED_BUILTIN
+  #define LED_BUILTIN       13
+#endif
+
+#ifndef LED_BLUE
+  #define LED_BLUE          2
+#endif
+
+#ifndef LED_RED
+  #define LED_RED           3
+#endif
+
+#define USING_HW_TIMER_INTERVAL_MS        false   //true
+
+// Don't change these numbers to make higher Timer freq. System can hang
+#define HW_TIMER_INTERVAL_US        10L
+#define HW_TIMER_INTERVAL_FREQ      100000L
+
+volatile uint32_t startMicros = 0;
+
+// Init SAMDUE_Slow_PWM, each can service 16 different ISR-based PWM channels
+SAMDUE_Slow_PWM ISR_PWM;
+
+//////////////////////////////////////////////////////
+
+void TimerHandler()
+{ 
+  ISR_PWM.run();
+}
+
+//////////////////////////////////////////////////////
+
+#define USING_PWM_FREQUENCY     false   //true
+
+//////////////////////////////////////////////////////
+
+// You can assign pins here. Be carefull to select good pin to use or crash
+uint32_t PWM_Pin    = LED_BUILTIN;
+
+// You can assign any interval for any timer here, in Hz
+double PWM_Freq1   = 1.0f;
+// You can assign any interval for any timer here, in Hz
+double PWM_Freq2   = 2.0f;
+
+// You can assign any interval for any timer here, in microseconds
+uint32_t PWM_Period1 = 1000000 / PWM_Freq1;
+// You can assign any interval for any timer here, in microseconds
+uint32_t PWM_Period2 = 1000000 / PWM_Freq2;
+
+// You can assign any duty_cycle for any PWM here, from 0-100
+uint32_t PWM_DutyCycle1  = 50;
+// You can assign any duty_cycle for any PWM here, from 0-100
+uint32_t PWM_DutyCycle2  = 90;
+
+// Channel number used to identify associated channel
+int channelNum;
+
+////////////////////////////////////////////////
+
+uint16_t attachDueInterrupt(double microseconds, timerCallback callback, const char* TimerName)
+{
+  DueTimerInterrupt dueTimerInterrupt = DueTimer.getAvailable();
+  
+  dueTimerInterrupt.attachInterruptInterval(microseconds, callback);
+
+  uint16_t timerNumber = dueTimerInterrupt.getTimerNumber();
+  
+  Serial.print(TimerName); Serial.print(F(" attached to Timer(")); Serial.print(timerNumber); Serial.println(F(")"));
+
+  return timerNumber;
+}
+
+////////////////////////////////////////////////
+
+void setup()
+{
+  Serial.begin(115200);
+  while (!Serial);
+
+  delay(2000);
+
+  Serial.print(F("\nStarting ISR_Changing_PWM on ")); Serial.println(BOARD_NAME);
+  Serial.println(SAMDUE_SLOW_PWM_VERSION);
+  Serial.print(F("CPU Frequency = ")); Serial.print(F_CPU / 1000000); Serial.println(F(" MHz"));
+  Serial.print(F("Timer Frequency = ")); Serial.print(SystemCoreClock / 1000000); Serial.println(F(" MHz"));
+
+  // Interval in microsecs
+  attachDueInterrupt(HW_TIMER_INTERVAL_US, TimerHandler, "ITimer");
+}
+
+void loop()
+{
+  Serial.print(F("Using PWM Freq = ")); Serial.print(PWM_Freq1); Serial.print(F(", PWM DutyCycle = ")); Serial.println(PWM_DutyCycle1);
+
+#if USING_PWM_FREQUENCY
+  // You can use this with PWM_Freq in Hz
+  channelNum = ISR_PWM.setPWM(PWM_Pin, PWM_Freq1, PWM_DutyCycle1);
+#else
+  // Or using period in microsecs resolution
+  channelNum = ISR_PWM.setPWM_Period(PWM_Pin, PWM_Period1, PWM_DutyCycle1);
+#endif
+
+  delay(10000);
+
+  ISR_PWM.deleteChannel((unsigned) channelNum);
+
+  Serial.print(F("Using PWM Freq = ")); Serial.print(PWM_Freq2); Serial.print(F(", PWM DutyCycle = ")); Serial.println(PWM_DutyCycle2);
+
+#if USING_PWM_FREQUENCY
+  // You can use this with PWM_Freq in Hz
+  channelNum = ISR_PWM.setPWM(PWM_Pin, PWM_Freq2, PWM_DutyCycle2);
+#else
+  // Or using period in microsecs resolution
+  channelNum = ISR_PWM.setPWM_Period(PWM_Pin, PWM_Period2, PWM_DutyCycle2);
+#endif
+
+  delay(10000);
+
+  ISR_PWM.deleteChannel((unsigned) channelNum);
+}
diff --git a/examples/ISR_Modify_PWM/ISR_Modify_PWM.ino b/examples/ISR_Modify_PWM/ISR_Modify_PWM.ino
new file mode 100644
index 0000000..848cf4a
--- /dev/null
+++ b/examples/ISR_Modify_PWM/ISR_Modify_PWM.ino
@@ -0,0 +1,184 @@
+/****************************************************************************************************************************
+  ISR_Modify_PWM.ino
+  For Arduino SAM_DUE boards
+  Written by Khoi Hoang
+
+  Built by Khoi Hoang https://github.com/khoih-prog/SAMDUE_Slow_PWM
+  Licensed under MIT license
+  
+  Now even you use all these new 16 ISR-based timers,with their maximum interval practically unlimited (limited only by
+  unsigned long miliseconds), you just consume only one megaAVR-based timer and avoid conflicting with other cores' tasks.
+  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.
+*****************************************************************************************************************************/
+
+#if !( defined(ARDUINO_SAM_DUE) || defined(__SAM3X8E__) )
+  #error This is designed only for Arduino SAM_DUE board! Please check your Tools->Board setting.
+#endif
+
+// These define's must be placed at the beginning before #include "ESP32_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_      3
+
+#include "SAMDUE_Slow_PWM.h"
+
+#define LED_OFF             HIGH
+#define LED_ON              LOW
+
+#ifndef LED_BUILTIN
+  #define LED_BUILTIN       13
+#endif
+
+#ifndef LED_BLUE
+  #define LED_BLUE          2
+#endif
+
+#ifndef LED_RED
+  #define LED_RED           3
+#endif
+
+#define USING_HW_TIMER_INTERVAL_MS        false   //true
+
+// Don't change these numbers to make higher Timer freq. System can hang
+#define HW_TIMER_INTERVAL_US        10L
+#define HW_TIMER_INTERVAL_FREQ      100000L
+
+volatile uint32_t startMicros = 0;
+
+// Init SAMDUE_Slow_PWM, each can service 16 different ISR-based PWM channels
+SAMDUE_Slow_PWM ISR_PWM;
+
+//////////////////////////////////////////////////////
+
+void TimerHandler()
+{ 
+  ISR_PWM.run();
+}
+
+//////////////////////////////////////////////////////
+
+#define USING_PWM_FREQUENCY     false //true
+
+//////////////////////////////////////////////////////
+
+// You can assign pins here. Be carefull to select good pin to use or crash
+uint32_t PWM_Pin    = LED_BUILTIN;
+
+// You can assign any interval for any timer here, in Hz
+double PWM_Freq1   = 1.0f;
+// You can assign any interval for any timer here, in Hz
+double PWM_Freq2   = 2.0f;
+
+// You can assign any interval for any timer here, in microseconds
+uint32_t PWM_Period1 = 1000000 / PWM_Freq1;
+// You can assign any interval for any timer here, in microseconds
+uint32_t PWM_Period2 = 1000000 / PWM_Freq2;
+
+// You can assign any duty_cycle for any PWM here, from 0-100
+uint32_t PWM_DutyCycle1  = 10;
+// You can assign any duty_cycle for any PWM here, from 0-100
+uint32_t PWM_DutyCycle2  = 90;
+
+// Channel number used to identify associated channel
+int channelNum;
+
+////////////////////////////////////////////////
+
+uint16_t attachDueInterrupt(double microseconds, timerCallback callback, const char* TimerName)
+{
+  DueTimerInterrupt dueTimerInterrupt = DueTimer.getAvailable();
+  
+  dueTimerInterrupt.attachInterruptInterval(microseconds, callback);
+
+  uint16_t timerNumber = dueTimerInterrupt.getTimerNumber();
+  
+  Serial.print(TimerName); Serial.print(F(" attached to Timer(")); Serial.print(timerNumber); Serial.println(F(")"));
+
+  return timerNumber;
+}
+
+////////////////////////////////////////////////
+
+void setup()
+{
+  Serial.begin(115200);
+  while (!Serial);
+
+  delay(2000);
+
+  Serial.print(F("\nStarting ISR_Modify_PWM on ")); Serial.println(BOARD_NAME);
+  Serial.println(SAMDUE_SLOW_PWM_VERSION);
+  Serial.print(F("CPU Frequency = ")); Serial.print(F_CPU / 1000000); Serial.println(F(" MHz"));
+  Serial.print(F("Timer Frequency = ")); Serial.print(SystemCoreClock / 1000000); Serial.println(F(" MHz"));
+
+  // Interval in microsecs
+  attachDueInterrupt(HW_TIMER_INTERVAL_US, TimerHandler, "ITimer");
+
+  Serial.print(F("Using PWM Freq = ")); Serial.print(PWM_Freq1); Serial.print(F(", PWM DutyCycle = ")); Serial.println(PWM_DutyCycle1);
+
+#if USING_PWM_FREQUENCY
+  // You can use this with PWM_Freq in Hz
+  ISR_PWM.setPWM(PWM_Pin, PWM_Freq1, PWM_DutyCycle1);
+#else
+  // Or using period in microsecs resolution
+  channelNum = ISR_PWM.setPWM_Period(PWM_Pin, PWM_Period1, PWM_DutyCycle1);
+#endif
+}
+
+////////////////////////////////////////////////
+
+void changePWM()
+{
+  static uint8_t count = 1;
+
+  double PWM_Freq;
+  uint32_t PWM_DutyCycle;
+
+  if (count++ % 2)
+  {
+    PWM_Freq        = PWM_Freq2;
+    PWM_DutyCycle   = PWM_DutyCycle2;
+  }
+  else
+  {
+    PWM_Freq        = PWM_Freq1;
+    PWM_DutyCycle   = PWM_DutyCycle1;
+  }
+
+  // You can use this with PWM_Freq in Hz
+  if (!ISR_PWM.modifyPWMChannel(channelNum, PWM_Pin, PWM_Freq, PWM_DutyCycle))
+  {
+    Serial.println(F("modifyPWMChannel error for PWM_Period"));
+  }
+}
+
+////////////////////////////////////////////////
+
+void changingPWM()
+{
+  static unsigned long changingPWM_timeout = 0;
+
+  static unsigned long current_millis;
+
+#define CHANGING_PWM_INTERVAL    10000L
+
+  current_millis = millis();
+
+  // changePWM every CHANGING_PWM_INTERVAL (10) seconds.
+  if ( (current_millis > changingPWM_timeout) )
+  {
+    if (changingPWM_timeout > 0)
+      changePWM();
+
+    changingPWM_timeout = current_millis + CHANGING_PWM_INTERVAL;
+  }
+}
+
+////////////////////////////////////////////////
+
+void loop()
+{
+  changingPWM();
+}
diff --git a/keywords.txt b/keywords.txt
index 9c880cd..ac06920 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -36,6 +36,8 @@ init  KEYWORD2
 run KEYWORD2
 setPWM  KEYWORD2
 setPWM_Period  KEYWORD2
+modifyPWMChannel  KEYWORD2
+modifyPWMChannel_Period KEYWORD2
 deleteChannel KEYWORD2
 restartChannel  KEYWORD2
 isEnabled KEYWORD2
diff --git a/library.json b/library.json
index 13386fd..f674877 100644
--- a/library.json
+++ b/library.json
@@ -1,8 +1,8 @@
 {
   "name": "SAMDUE_Slow_PWM",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "keywords": "timer, interrupt, hardware, isr, isr-based, pwm, isr-based-pwm, timing, control, device, hardware-timer, mission-critical, accuracy, precise, sam, due, sam-due, sam3x8e, atmel-sam",
-  "description": "This library enables you to use ISR-based PWM channels on an Arduino SAM_DUE board to create and output PWM any GPIO pin. It now supports 16 ISR-based PWM channels, while consuming only 1 Hardware Timer. PWM channel interval can be very long (ulong microsecs / millisecs). The most important feature is they're ISR-based PWM channels, supporting lower PWM frequencies with suitable accuracy. Their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. These ISR-based PWMs, 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 PWM using millis() or micros(). That's necessary if you need to control devices requiring high precision",
+  "description": "This library enables you to use ISR-based PWM channels on an Arduino SAM_DUE board to create and output PWM any GPIO pin. It now supports 16 ISR-based PWM channels, while consuming only 1 Hardware Timer. PWM channel interval can be very long (ulong microsecs / millisecs). The most important feature is they're ISR-based PWM channels, supporting lower PWM frequencies with suitable accuracy. Their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. These ISR-based PWMs, 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 PWM using millis() or micros(). That's necessary if you need to control devices requiring high precision. Now you can change the PWM settings on-the-fly",
   "authors":
   {
     "name":  "Khoi Hoang",
diff --git a/library.properties b/library.properties
index 718ca1e..12d10e7 100644
--- a/library.properties
+++ b/library.properties
@@ -1,9 +1,9 @@
 name=SAMDUE_Slow_PWM
-version=1.0.0
+version=1.1.0
 author=Khoi Hoang
 maintainer=Khoi Hoang <khoih.prog@gmail.com>
 sentence=This library enables you to use ISR-based PWM channels on an Arduino SAM_DUE board to create and output PWM any GPIO pin.
-paragraph=It now supports 16 ISR-based PWM channels, while consuming only 1 Hardware Timer. PWM channel interval can be very long (ulong microsecs / millisecs). The most important feature is they're ISR-based PWM channels, supporting lower PWM frequencies with suitable accuracy. Their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. These ISR-based PWMs, 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 PWM using millis() or micros(). That's necessary if you need to control devices requiring high precision
+paragraph=It now supports 16 ISR-based PWM channels, while consuming only 1 Hardware Timer. PWM channel interval can be very long (ulong microsecs / millisecs). The most important feature is they are ISR-based PWM channels, supporting lower PWM frequencies with suitable accuracy. Their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. These ISR-based PWMs, 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 PWM using millis() or micros(). That is necessary if you need to control devices requiring high precision. Now you can change the PWM settings on-the-fly
 category=Device Control
 url=https://github.com/khoih-prog/SAMDUE_Slow_PWM
 architectures=sam,atmelsam
diff --git a/src/PWM_Generic_Debug.h b/src/PWM_Generic_Debug.h
index 3a95154..00afb64 100644
--- a/src/PWM_Generic_Debug.h
+++ b/src/PWM_Generic_Debug.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
  *****************************************************************************************************************************/
 
 #pragma once
diff --git a/src/SAMDUE_Slow_PWM.h b/src/SAMDUE_Slow_PWM.h
index 81a5b6a..080556a 100644
--- a/src/SAMDUE_Slow_PWM.h
+++ b/src/SAMDUE_Slow_PWM.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -37,7 +38,7 @@
 #endif
 
 #ifndef SAMDUE_SLOW_PWM_VERSION
-  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.0.0")
+  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.1.0")
 #endif
 
 #ifndef _PWM_LOGLEVEL_
diff --git a/src/SAMDUE_Slow_PWM_ISR.h b/src/SAMDUE_Slow_PWM_ISR.h
index 008bbd7..5661e1d 100644
--- a/src/SAMDUE_Slow_PWM_ISR.h
+++ b/src/SAMDUE_Slow_PWM_ISR.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -33,7 +34,7 @@
 #endif
 
 #ifndef SAMDUE_SLOW_PWM_VERSION
-  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.0.0")
+  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.1.0")
 #endif
 
 #ifndef _PWM_LOGLEVEL_
@@ -80,30 +81,61 @@ class SAMDUE_SLOW_PWM_ISR
     
     //////////////////////////////////////////////////////////////////
     // PWM
-    void setPWM(uint32_t pin, uint32_t frequency, uint32_t dutycycle, timer_callback StartCallback = nullptr,
+    // Return the channelNum if OK, -1 if error
+    int setPWM(uint32_t pin, double frequency, uint32_t dutycycle, timer_callback StartCallback = nullptr, 
                 timer_callback StopCallback = nullptr)
     {
       uint32_t period = 0;
-      
+
       if ( ( frequency != 0 ) && ( frequency <= 1000 ) )
       {
-      // period in us
-      period = 1000000.0f / frequency;
+        // period in us
+        period = 1000000.0f / frequency;
       }
       else
       {       
-        PWM_LOGERROR(F("Error: Invalid frequency, max is 1000Hz"));
+        PWM_LOGERROR("Error: Invalid frequency, max is 1000Hz");
+        
+        return -1;
       }
       
-      setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);     
+      return setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);   
     }
 
-    //period in us
-    void setPWM_Period(uint32_t pin, uint32_t period, uint32_t dutycycle, timer_callback StartCallback = nullptr,
-                       timer_callback StopCallback = nullptr)
+    // period in us
+    // Return the channelNum if OK, -1 if error
+    int setPWM_Period(uint32_t pin, uint32_t period, uint32_t dutycycle, timer_callback StartCallback = nullptr,
+                       timer_callback StopCallback = nullptr)  
     {     
-      setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);       
-    }    
+      return setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);      
+    } 
+    
+    //////////////////////////////////////////////////////////////////
+    
+    // low level function to modify a PWM channel
+    // returns the true on success or false on failure
+    bool modifyPWMChannel(unsigned channelNum, uint32_t pin, double frequency, uint32_t dutycycle)
+    {
+      uint32_t period = 0;
+      
+      if ( ( frequency > 0 ) && ( frequency <= 1000 ) )
+      {
+        // period in us
+        period = 1000000.0f / frequency;
+      }
+      else
+      {       
+        PWM_LOGERROR("Error: Invalid frequency, max is 1000Hz");
+        return false;
+      }
+      
+      return modifyPWMChannel_Period(channelNum, pin, period, dutycycle);
+    }
+    
+    //////////////////////////////////////////////////////////////////
+    
+    //period in us
+    bool modifyPWMChannel_Period(unsigned channelNum, uint32_t pin, uint32_t period, uint32_t dutycycle);
     
     //////////////////////////////////////////////////////////////////
 
diff --git a/src/SAMDUE_Slow_PWM_ISR.hpp b/src/SAMDUE_Slow_PWM_ISR.hpp
index bd90cf4..ee13442 100644
--- a/src/SAMDUE_Slow_PWM_ISR.hpp
+++ b/src/SAMDUE_Slow_PWM_ISR.hpp
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -170,6 +171,8 @@ int SAMDUE_SLOW_PWM_ISR::setupPWMChannel(uint32_t pin, uint32_t period, uint32_t
   digitalWrite(pin, HIGH);
   SAM_DUE_PWM[channelNum].pinHigh       = true;
   
+  SAM_DUE_PWM[channelNum].prevTime      = timeNow();
+  
   SAM_DUE_PWM[channelNum].callbackStart = cbStartFunc;
   SAM_DUE_PWM[channelNum].callbackStop  = cbStopFunc;
   
@@ -185,6 +188,44 @@ int SAMDUE_SLOW_PWM_ISR::setupPWMChannel(uint32_t pin, uint32_t period, uint32_t
   return channelNum;
 }
 
+///////////////////////////////////////////////////
+
+bool SAMDUE_SLOW_PWM_ISR::modifyPWMChannel_Period(unsigned channelNum, uint32_t pin, uint32_t period, uint32_t dutycycle)
+{
+  // Invalid input, such as period = 0, etc
+  if ( (period == 0) || (dutycycle > 100) )
+  {
+    PWM_LOGERROR("Error: Invalid period or dutycycle");
+    return false;
+  }
+
+  if (channelNum > MAX_NUMBER_CHANNELS) 
+  {
+    PWM_LOGERROR("Error: channelNum > MAX_NUMBER_CHANNELS");
+    return false;
+  }
+  
+  if (SAM_DUE_PWM[channelNum].pin != pin) 
+  {
+    PWM_LOGERROR("Error: channelNum and pin mismatched");
+    return false;
+  }
+   
+  SAM_DUE_PWM[channelNum].period        = period;
+  SAM_DUE_PWM[channelNum].onTime        = ( period * dutycycle ) / 100;
+  
+  digitalWrite(pin, HIGH);
+  SAM_DUE_PWM[channelNum].pinHigh       = true;
+  
+  SAM_DUE_PWM[channelNum].prevTime      = timeNow();
+     
+  PWM_LOGINFO0("Channel : "); PWM_LOGINFO0(channelNum); PWM_LOGINFO0("\tPeriod : "); PWM_LOGINFO0(SAM_DUE_PWM[channelNum].period);
+  PWM_LOGINFO0("\t\tOnTime : "); PWM_LOGINFO0(SAM_DUE_PWM[channelNum].onTime); PWM_LOGINFO0("\tStart_Time : "); PWM_LOGINFOLN0(SAM_DUE_PWM[channelNum].prevTime);
+  
+  return true;
+}
+
+
 ///////////////////////////////////////////////////
 
 void SAMDUE_SLOW_PWM_ISR::deleteChannel(unsigned channelNum) 
diff --git a/src_cpp/PWM_Generic_Debug.h b/src_cpp/PWM_Generic_Debug.h
index 3a95154..00afb64 100644
--- a/src_cpp/PWM_Generic_Debug.h
+++ b/src_cpp/PWM_Generic_Debug.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
  *****************************************************************************************************************************/
 
 #pragma once
diff --git a/src_cpp/SAMDUE_Slow_PWM.h b/src_cpp/SAMDUE_Slow_PWM.h
index 81a5b6a..080556a 100644
--- a/src_cpp/SAMDUE_Slow_PWM.h
+++ b/src_cpp/SAMDUE_Slow_PWM.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -37,7 +38,7 @@
 #endif
 
 #ifndef SAMDUE_SLOW_PWM_VERSION
-  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.0.0")
+  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.1.0")
 #endif
 
 #ifndef _PWM_LOGLEVEL_
diff --git a/src_cpp/SAMDUE_Slow_PWM_ISR.cpp b/src_cpp/SAMDUE_Slow_PWM_ISR.cpp
index 009b165..4d5dd71 100644
--- a/src_cpp/SAMDUE_Slow_PWM_ISR.cpp
+++ b/src_cpp/SAMDUE_Slow_PWM_ISR.cpp
@@ -12,16 +12,18 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
-#include <string.h>
 #include "SAMDUE_Slow_PWM_ISR.h"
 
+#include <string.h>
+
 /////////////////////////////////////////////////// 
 
 
@@ -166,6 +168,8 @@ int SAMDUE_SLOW_PWM_ISR::setupPWMChannel(uint32_t pin, uint32_t period, uint32_t
   digitalWrite(pin, HIGH);
   SAM_DUE_PWM[channelNum].pinHigh       = true;
   
+  SAM_DUE_PWM[channelNum].prevTime      = timeNow();
+  
   SAM_DUE_PWM[channelNum].callbackStart = cbStartFunc;
   SAM_DUE_PWM[channelNum].callbackStop  = cbStopFunc;
   
@@ -181,6 +185,44 @@ int SAMDUE_SLOW_PWM_ISR::setupPWMChannel(uint32_t pin, uint32_t period, uint32_t
   return channelNum;
 }
 
+///////////////////////////////////////////////////
+
+bool SAMDUE_SLOW_PWM_ISR::modifyPWMChannel_Period(unsigned channelNum, uint32_t pin, uint32_t period, uint32_t dutycycle)
+{
+  // Invalid input, such as period = 0, etc
+  if ( (period == 0) || (dutycycle > 100) )
+  {
+    PWM_LOGERROR("Error: Invalid period or dutycycle");
+    return false;
+  }
+
+  if (channelNum > MAX_NUMBER_CHANNELS) 
+  {
+    PWM_LOGERROR("Error: channelNum > MAX_NUMBER_CHANNELS");
+    return false;
+  }
+  
+  if (SAM_DUE_PWM[channelNum].pin != pin) 
+  {
+    PWM_LOGERROR("Error: channelNum and pin mismatched");
+    return false;
+  }
+   
+  SAM_DUE_PWM[channelNum].period        = period;
+  SAM_DUE_PWM[channelNum].onTime        = ( period * dutycycle ) / 100;
+  
+  digitalWrite(pin, HIGH);
+  SAM_DUE_PWM[channelNum].pinHigh       = true;
+  
+  SAM_DUE_PWM[channelNum].prevTime      = timeNow();
+     
+  PWM_LOGINFO0("Channel : "); PWM_LOGINFO0(channelNum); PWM_LOGINFO0("\tPeriod : "); PWM_LOGINFO0(SAM_DUE_PWM[channelNum].period);
+  PWM_LOGINFO0("\t\tOnTime : "); PWM_LOGINFO0(SAM_DUE_PWM[channelNum].onTime); PWM_LOGINFO0("\tStart_Time : "); PWM_LOGINFOLN0(SAM_DUE_PWM[channelNum].prevTime);
+  
+  return true;
+}
+
+
 ///////////////////////////////////////////////////
 
 void SAMDUE_SLOW_PWM_ISR::deleteChannel(unsigned channelNum) 
@@ -305,3 +347,4 @@ unsigned SAMDUE_SLOW_PWM_ISR::getnumChannels()
 }
 
 
+
diff --git a/src_cpp/SAMDUE_Slow_PWM_ISR.h b/src_cpp/SAMDUE_Slow_PWM_ISR.h
index 58771ab..8e1d212 100644
--- a/src_cpp/SAMDUE_Slow_PWM_ISR.h
+++ b/src_cpp/SAMDUE_Slow_PWM_ISR.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -33,7 +34,7 @@
 #endif
 
 #ifndef SAMDUE_SLOW_PWM_VERSION
-  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.0.0")
+  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.1.0")
 #endif
 
 #ifndef _PWM_LOGLEVEL_
@@ -80,30 +81,61 @@ class SAMDUE_SLOW_PWM_ISR
     
     //////////////////////////////////////////////////////////////////
     // PWM
-    void setPWM(uint32_t pin, uint32_t frequency, uint32_t dutycycle, timer_callback StartCallback = nullptr,
+    // Return the channelNum if OK, -1 if error
+    int setPWM(uint32_t pin, double frequency, uint32_t dutycycle, timer_callback StartCallback = nullptr, 
                 timer_callback StopCallback = nullptr)
     {
       uint32_t period = 0;
-      
+
       if ( ( frequency != 0 ) && ( frequency <= 1000 ) )
       {
-      // period in us
-      period = 1000000.0f / frequency;
+        // period in us
+        period = 1000000.0f / frequency;
       }
       else
       {       
-        PWM_LOGERROR(F("Error: Invalid frequency, max is 1000Hz"));
+        PWM_LOGERROR("Error: Invalid frequency, max is 1000Hz");
+        
+        return -1;
       }
       
-      setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);     
+      return setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);   
     }
 
-    //period in us
-    void setPWM_Period(uint32_t pin, uint32_t period, uint32_t dutycycle, timer_callback StartCallback = nullptr,
-                       timer_callback StopCallback = nullptr)
+    // period in us
+    // Return the channelNum if OK, -1 if error
+    int setPWM_Period(uint32_t pin, uint32_t period, uint32_t dutycycle, timer_callback StartCallback = nullptr,
+                       timer_callback StopCallback = nullptr)  
     {     
-      setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);       
-    }    
+      return setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);      
+    } 
+    
+    //////////////////////////////////////////////////////////////////
+    
+    // low level function to modify a PWM channel
+    // returns the true on success or false on failure
+    bool modifyPWMChannel(unsigned channelNum, uint32_t pin, double frequency, uint32_t dutycycle)
+    {
+      uint32_t period = 0;
+      
+      if ( ( frequency > 0 ) && ( frequency <= 1000 ) )
+      {
+        // period in us
+        period = 1000000.0f / frequency;
+      }
+      else
+      {       
+        PWM_LOGERROR("Error: Invalid frequency, max is 1000Hz");
+        return false;
+      }
+      
+      return modifyPWMChannel_Period(channelNum, pin, period, dutycycle);
+    }
+    
+    //////////////////////////////////////////////////////////////////
+    
+    //period in us
+    bool modifyPWMChannel_Period(unsigned channelNum, uint32_t pin, uint32_t period, uint32_t dutycycle);
     
     //////////////////////////////////////////////////////////////////
 
diff --git a/src_h/PWM_Generic_Debug.h b/src_h/PWM_Generic_Debug.h
index 3a95154..00afb64 100644
--- a/src_h/PWM_Generic_Debug.h
+++ b/src_h/PWM_Generic_Debug.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
  *****************************************************************************************************************************/
 
 #pragma once
diff --git a/src_h/SAMDUE_Slow_PWM.h b/src_h/SAMDUE_Slow_PWM.h
index 81a5b6a..080556a 100644
--- a/src_h/SAMDUE_Slow_PWM.h
+++ b/src_h/SAMDUE_Slow_PWM.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -37,7 +38,7 @@
 #endif
 
 #ifndef SAMDUE_SLOW_PWM_VERSION
-  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.0.0")
+  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.1.0")
 #endif
 
 #ifndef _PWM_LOGLEVEL_
diff --git a/src_h/SAMDUE_Slow_PWM_ISR.h b/src_h/SAMDUE_Slow_PWM_ISR.h
index 008bbd7..5661e1d 100644
--- a/src_h/SAMDUE_Slow_PWM_ISR.h
+++ b/src_h/SAMDUE_Slow_PWM_ISR.h
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -33,7 +34,7 @@
 #endif
 
 #ifndef SAMDUE_SLOW_PWM_VERSION
-  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.0.0")
+  #define SAMDUE_SLOW_PWM_VERSION       F("SAMDUE_Slow_PWM v1.1.0")
 #endif
 
 #ifndef _PWM_LOGLEVEL_
@@ -80,30 +81,61 @@ class SAMDUE_SLOW_PWM_ISR
     
     //////////////////////////////////////////////////////////////////
     // PWM
-    void setPWM(uint32_t pin, uint32_t frequency, uint32_t dutycycle, timer_callback StartCallback = nullptr,
+    // Return the channelNum if OK, -1 if error
+    int setPWM(uint32_t pin, double frequency, uint32_t dutycycle, timer_callback StartCallback = nullptr, 
                 timer_callback StopCallback = nullptr)
     {
       uint32_t period = 0;
-      
+
       if ( ( frequency != 0 ) && ( frequency <= 1000 ) )
       {
-      // period in us
-      period = 1000000.0f / frequency;
+        // period in us
+        period = 1000000.0f / frequency;
       }
       else
       {       
-        PWM_LOGERROR(F("Error: Invalid frequency, max is 1000Hz"));
+        PWM_LOGERROR("Error: Invalid frequency, max is 1000Hz");
+        
+        return -1;
       }
       
-      setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);     
+      return setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);   
     }
 
-    //period in us
-    void setPWM_Period(uint32_t pin, uint32_t period, uint32_t dutycycle, timer_callback StartCallback = nullptr,
-                       timer_callback StopCallback = nullptr)
+    // period in us
+    // Return the channelNum if OK, -1 if error
+    int setPWM_Period(uint32_t pin, uint32_t period, uint32_t dutycycle, timer_callback StartCallback = nullptr,
+                       timer_callback StopCallback = nullptr)  
     {     
-      setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);       
-    }    
+      return setupPWMChannel(pin, period, dutycycle, (void *) StartCallback, (void *) StopCallback);      
+    } 
+    
+    //////////////////////////////////////////////////////////////////
+    
+    // low level function to modify a PWM channel
+    // returns the true on success or false on failure
+    bool modifyPWMChannel(unsigned channelNum, uint32_t pin, double frequency, uint32_t dutycycle)
+    {
+      uint32_t period = 0;
+      
+      if ( ( frequency > 0 ) && ( frequency <= 1000 ) )
+      {
+        // period in us
+        period = 1000000.0f / frequency;
+      }
+      else
+      {       
+        PWM_LOGERROR("Error: Invalid frequency, max is 1000Hz");
+        return false;
+      }
+      
+      return modifyPWMChannel_Period(channelNum, pin, period, dutycycle);
+    }
+    
+    //////////////////////////////////////////////////////////////////
+    
+    //period in us
+    bool modifyPWMChannel_Period(unsigned channelNum, uint32_t pin, uint32_t period, uint32_t dutycycle);
     
     //////////////////////////////////////////////////////////////////
 
diff --git a/src_h/SAMDUE_Slow_PWM_ISR.hpp b/src_h/SAMDUE_Slow_PWM_ISR.hpp
index bd90cf4..ee13442 100644
--- a/src_h/SAMDUE_Slow_PWM_ISR.hpp
+++ b/src_h/SAMDUE_Slow_PWM_ISR.hpp
@@ -12,11 +12,12 @@
   Therefore, their executions are not blocked by bad-behaving functions / tasks.
   This important feature is absolutely necessary for mission-critical tasks.
 
-  Version: 1.0.0
+  Version: 1.1.0
 
   Version Modified By   Date      Comments
   ------- -----------  ---------- -----------
   1.0.0   K.Hoang      29/09/2021 Initial coding for Arduino SAM_DUE
+  1.1.0   K Hoang      10/11/2021 Add functions to modify PWM settings on-the-fly
 *****************************************************************************************************************************/
 
 #pragma once
@@ -170,6 +171,8 @@ int SAMDUE_SLOW_PWM_ISR::setupPWMChannel(uint32_t pin, uint32_t period, uint32_t
   digitalWrite(pin, HIGH);
   SAM_DUE_PWM[channelNum].pinHigh       = true;
   
+  SAM_DUE_PWM[channelNum].prevTime      = timeNow();
+  
   SAM_DUE_PWM[channelNum].callbackStart = cbStartFunc;
   SAM_DUE_PWM[channelNum].callbackStop  = cbStopFunc;
   
@@ -185,6 +188,44 @@ int SAMDUE_SLOW_PWM_ISR::setupPWMChannel(uint32_t pin, uint32_t period, uint32_t
   return channelNum;
 }
 
+///////////////////////////////////////////////////
+
+bool SAMDUE_SLOW_PWM_ISR::modifyPWMChannel_Period(unsigned channelNum, uint32_t pin, uint32_t period, uint32_t dutycycle)
+{
+  // Invalid input, such as period = 0, etc
+  if ( (period == 0) || (dutycycle > 100) )
+  {
+    PWM_LOGERROR("Error: Invalid period or dutycycle");
+    return false;
+  }
+
+  if (channelNum > MAX_NUMBER_CHANNELS) 
+  {
+    PWM_LOGERROR("Error: channelNum > MAX_NUMBER_CHANNELS");
+    return false;
+  }
+  
+  if (SAM_DUE_PWM[channelNum].pin != pin) 
+  {
+    PWM_LOGERROR("Error: channelNum and pin mismatched");
+    return false;
+  }
+   
+  SAM_DUE_PWM[channelNum].period        = period;
+  SAM_DUE_PWM[channelNum].onTime        = ( period * dutycycle ) / 100;
+  
+  digitalWrite(pin, HIGH);
+  SAM_DUE_PWM[channelNum].pinHigh       = true;
+  
+  SAM_DUE_PWM[channelNum].prevTime      = timeNow();
+     
+  PWM_LOGINFO0("Channel : "); PWM_LOGINFO0(channelNum); PWM_LOGINFO0("\tPeriod : "); PWM_LOGINFO0(SAM_DUE_PWM[channelNum].period);
+  PWM_LOGINFO0("\t\tOnTime : "); PWM_LOGINFO0(SAM_DUE_PWM[channelNum].onTime); PWM_LOGINFO0("\tStart_Time : "); PWM_LOGINFOLN0(SAM_DUE_PWM[channelNum].prevTime);
+  
+  return true;
+}
+
+
 ///////////////////////////////////////////////////
 
 void SAMDUE_SLOW_PWM_ISR::deleteChannel(unsigned channelNum)