v1.1.1

### Releases v1.1.1

1. Add example [**Change_Interval**](examples/Change_Interval) and [**ISR_16_Timers_Array_Complex**](examples/ISR_16_Timers_Array_Complex)
2. Bump up version to sync with other TimerInterrupt Libraries. Modify Version String.

Author: khoih-prog

.gitignore

@@ -0,0 +1,32 @@
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app

README.md

@@ -44,6 +44,11 @@ The catch is **your function is now part of an ISR (Interrupt Service Routine),
 ---
 ---
 
+### Releases v1.1.1
+
+1. Add example [**Change_Interval**](examples/Change_Interval) and [**ISR_16_Timers_Array_Complex**](examples/ISR_16_Timers_Array_Complex)
+2. Bump up version to sync with other TimerInterrupt Libraries. Modify Version String.
+
 ### Releases v1.0.1
 
 1. Add complicated example [ISR_16_Timers_Array](examples/ISR_16_Timers_Array) utilizing and demonstrating the full usage of 16 independent ISR Timers.
@@ -63,7 +68,7 @@ The catch is **your function is now part of an ISR (Interrupt Service Routine),
 ---
 ---
 
-## Prerequisite
+## Prerequisites
 
  1. [`Arduino IDE 1.8.13+` for Arduino](https://www.arduino.cc/en/Main/Software)
  2. [`Arduino SAMD core v1.8.9+`](https://www.arduino.cc/en/Guide/ArduinoM0) for SAMD ARM Cortex-M0+ boards (Nano 33 IoT, etc.).
@@ -101,7 +106,7 @@ Another way to install is to:
 
 1. Install [VS Code](https://code.visualstudio.com/)
 2. Install [PlatformIO](https://platformio.org/platformio-ide)
-3. Install [**SAMD_TimerInterrupt** library](https://platformio.org/lib/show/11396/SAMD_TimerInterrupt) by using [Library Manager](https://platformio.org/lib/show/11396/SAMD_TimerInterrupt/installation). Search for **SAMD_TimerInterrupt** in [Platform.io Author's Libraries](https://platformio.org/lib/search?query=author:%22Khoi%20Hoang%22)
+3. Install [**SAMD_TimerInterrupt** library](https://platformio.org/lib/show/11396/SAMD_TimerInterrupt) or [**SAMD_TimerInterrupt** library](https://platformio.org/lib/show/11396/SAMD_TimerInterrupt) by using [Library Manager](https://platformio.org/lib/show/11412/SAMD_TimerInterrupt/installation). Search for **SAMD_TimerInterrupt** in [Platform.io Author's Libraries](https://platformio.org/lib/search?query=author:%22Khoi%20Hoang%22)
 4. Use included [platformio.ini](platformio/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](https://docs.platformio.org/page/projectconf.html)
 
 ---
@@ -383,7 +388,9 @@ void setup()
  7. [SwitchDebounce](examples/SwitchDebounce)
  8. [TimerInterruptTest](examples/TimerInterruptTest)
  9. [TimerInterruptLEDDemo](examples/TimerInterruptLEDDemo)
-
+10. [**Change_Interval**](examples/Change_Interval). New
+11. [**ISR_16_Timers_Array_Complex**](examples/ISR_16_Timers_Array_Complex). New
+ 
 
 ---
 ---
@@ -591,7 +598,8 @@ void setup()
   while (!Serial);
   
   Serial.println("\nStarting ISR_Timer_Complex_WiFiNINA on " + String(BOARD_NAME));
-  Serial.println("Version : " + String(SAMD_TIMER_INTERRUPT_VERSION));
+  Serial.println(SAMD_TIMER_INTERRUPT_VERSION);
+  Serial.println("CPU Frequency = " + String(F_CPU / 1000000) + " MHz");
 
   // You need this timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary.
   blynkTimer.setInterval(BLYNK_TIMER_MS, blynkDoingSomething2s);
@@ -664,7 +672,8 @@ While software timer, **programmed for 2s, is activated after 7.937s !!!**. Then
 
 ```
 Starting ISR_Timer_Complex_WiFiNINA on SAMD_NANO_33_IOT
-Version : 1.0.1
+SAMDTimerInterrupt v1.1.1
+CPU Frequency = 48 MHz
 F_CPU (MHz) = 48, TIMER_HZ = 48
 TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
 Starting  ITimer OK, millis() = 810
@@ -726,7 +735,8 @@ blynkDoingSomething2s: Delta programmed ms = 2000, actual = 3002
 
 ```
 Starting TimerInterruptTest on ITSYBITSY_M4
-Version : 1.0.1
+SAMDTimerInterrupt v1.1.1
+CPU Frequency = 48 MHz
 F_CPU (MHz) = 120, TIMER_HZ = 48
 TC_Timer::startTimer _Timer = 0x4101c000, TC3 = 0x4101c000
 Starting  ITimer1 OK, millis() = 1820
@@ -801,7 +811,8 @@ ITimer0: millis() = 91018, delta = 1000
 
 ```
 Starting Argument_None on SAMD_NANO_33_IOT
-Version : 1.0.1
+SAMDTimerInterrupt v1.1.1
+CPU Frequency = 48 MHz
 F_CPU (MHz) = 48, TIMER_HZ = 48
 TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
 Starting  ITimer1 OK, millis() = 910
@@ -846,7 +857,8 @@ In this example, 16 independent ISR Timers are used, yet utilized just one Hardw
 
 ```
 Starting ISR_16_Timers_Array on SAMD_NANO_33_IOT
-Version : 1.0.1
+SAMDTimerInterrupt v1.1.1
+CPU Frequency = 48 MHz
 CPU Frequency = 48 MHz
 F_CPU (MHz) = 48, TIMER_HZ = 48
 TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
@@ -961,9 +973,76 @@ simpleTimerDoingSomething2s: Delta programmed ms = 2000, actual = 10000
 3s: Delta ms = 3000, ms = 34421
 11s: Delta ms = 11000, ms = 34421
 ```
+
+---
+
+5. The following is the sample terminal output when running example [Change_Interval](examples/Change_Interval) to demonstrate how to change Timer Interval on-the-fly
+
+```
+Starting Change_Interval on SAMD_NANO_33_IOT
+SAMDTimerInterrupt v1.1.1
+CPU Frequency = 48 MHz
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Starting  ITimer OK, millis() = 1131
+Time = 10001, TimerCount = 17
+Time = 20002, TimerCount = 37
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 1000
+Time = 30003, TimerCount = 47
+Time = 40004, TimerCount = 57
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 500
+Time = 50005, TimerCount = 77
+Time = 60006, TimerCount = 97
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 1000
+Time = 70007, TimerCount = 107
+Time = 80008, TimerCount = 117
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 500
+Time = 90009, TimerCount = 137
+Time = 100010, TimerCount = 157
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 1000
+Time = 110011, TimerCount = 167
+Time = 120012, TimerCount = 177
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 500
+Time = 130013, TimerCount = 197
+Time = 140014, TimerCount = 217
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 1000
+Time = 150015, TimerCount = 227
+Time = 160016, TimerCount = 237
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 500
+Time = 170017, TimerCount = 257
+Time = 180018, TimerCount = 277
+F_CPU (MHz) = 48, TIMER_HZ = 48
+TC_Timer::startTimer _Timer = 0x42002c00, TC3 = 0x42002c00
+Changing Interval, Timer = 1000
+Time = 190019, TimerCount = 287
+Time = 200020, TimerCount = 297
+
+```
+
 ---
 ---
 
+### Releases v1.1.1
+
+1. Add example [**Change_Interval**](examples/Change_Interval) and [**ISR_16_Timers_Array_Complex**](examples/ISR_16_Timers_Array_Complex)
+2. Bump up version to sync with other TimerInterrupt Libraries. Modify Version String.
+
 ### Releases v1.0.1
 
 1. Add complicated example [ISR_16_Timers_Array](examples/ISR_16_Timers_Array) utilizing and demonstrating the full usage of 16 independent ISR Timers.

examples/Argument_None/Argument_None.ino

@@ -19,12 +19,13 @@
    Based on BlynkTimer.h
    Author: Volodymyr Shymanskyy
 
-   Version: 1.0.1
+   Version: 1.1.1
 
    Version Modified By   Date      Comments
    ------- -----------  ---------- -----------
    1.0.0   K Hoang      30/10/2020 Initial coding
    1.0.1   K Hoang      06/11/2020 Add complicated example ISR_16_Timers_Array using all 16 independent ISR Timers.
+   1.1.1   K.Hoang      06/12/2020 Add Change_Interval example. Bump up version to sync with other TimerInterrupt Libraries
 *****************************************************************************************************************************/
 
 /*
@@ -152,7 +153,8 @@ void setup()
   delay(100);
 
   Serial.println("\nStarting Argument_None on " + String(BOARD_NAME));
-  Serial.println("Version : " + String(SAMD_TIMER_INTERRUPT_VERSION));
+  Serial.println(SAMD_TIMER_INTERRUPT_VERSION);
+  Serial.println("CPU Frequency = " + String(F_CPU / 1000000) + " MHz");
 
   // Interval in microsecs
   if (ITimer0.attachInterruptInterval(TIMER0_INTERVAL_MS * 1000, TimerHandler0))

examples/Change_Interval/Change_Interval.ino

@@ -0,0 +1,140 @@
+/****************************************************************************************************************************
+   Change_Interval.ino
+   For SAMD boards
+   Written by Khoi Hoang
+
+   Built by Khoi Hoang https://github.com/khoih-prog/SAMD_TimerInterrupt
+   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 SAMD 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.
+
+   Based on SimpleTimer - A timer library for Arduino.
+   Author: [email protected]
+   Copyright (c) 2010 OTTOTECNICA Italy
+
+   Based on BlynkTimer.h
+   Author: Volodymyr Shymanskyy
+
+   Version: 1.1.1
+
+   Version Modified By   Date      Comments
+   ------- -----------  ---------- -----------
+   1.0.0   K Hoang      30/10/2020 Initial coding
+   1.0.1   K Hoang      06/11/2020 Add complicated example ISR_16_Timers_Array using all 16 independent ISR Timers.
+   1.1.1   K.Hoang      06/12/2020 Add Change_Interval example. Bump up version to sync with other TimerInterrupt Libraries
+*****************************************************************************************************************************/
+
+/*
+   Notes:
+   Special design is necessary to share data between interrupt code and the rest of your program.
+   Variables usually need to be "volatile" types. Volatile tells the compiler to avoid optimizations that assume
+   variable can not spontaneously change. Because your function may change variables while your program is using them,
+   the compiler needs this hint. But volatile alone is often not enough.
+   When accessing shared variables, usually interrupts must be disabled. Even with volatile,
+   if the interrupt changes a multi-byte variable between a sequence of instructions, it can be read incorrectly.
+   If your data is multiple variables, such as an array and a count, usually interrupts need to be disabled
+   or the entire sequence of your code which accesses the data.
+*/
+
+#if !( defined(ARDUINO_SAMD_ZERO) || defined(ARDUINO_SAMD_MKR1000) || defined(ARDUINO_SAMD_MKRWIFI1010) \
+    || defined(ARDUINO_SAMD_NANO_33_IOT) || defined(ARDUINO_SAMD_MKRFox1200) || defined(ARDUINO_SAMD_MKRWAN1300) || defined(ARDUINO_SAMD_MKRWAN1310) \
+    || defined(ARDUINO_SAMD_MKRGSM1400) || defined(ARDUINO_SAMD_MKRNB1500) || defined(ARDUINO_SAMD_MKRVIDOR4000) || defined(__SAMD21G18A__) \
+    || defined(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD21E18A__) || defined(__SAMD51__) || defined(__SAMD51J20A__) || defined(__SAMD51J19A__) \
+    || defined(__SAMD51G19A__) || defined(__SAMD51P19A__) || defined(__SAMD21G18A__) )
+  #error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
+#endif
+
+// These define's must be placed at the beginning before #include "SAMDTimerInterrupt.h"
+// Don't define SAMD_TIMER_INTERRUPT_DEBUG > 2. Only for special ISR debugging only. Can hang the system.
+#define SAMD_TIMER_INTERRUPT_DEBUG      1
+
+#include "SAMDTimerInterrupt.h"
+
+//#ifndef LED_BUILTIN
+//  #define LED_BUILTIN       13
+//#endif
+
+#define TIMER_INTERVAL_MS        500   //1000
+
+volatile uint32_t TimerCount = 0;
+
+// Depending on the board, you can select SAMD21 Hardware Timer from TC3-TCC
+// SAMD21 Hardware Timer from TC3 or TCC
+// SAMD51 Hardware Timer only TC3
+
+// Init SAMD timer TIMER_TC3
+SAMDTimer ITimer(TIMER_TC3);
+
+void printResult(uint32_t currTime)
+{
+  Serial.println("Time = " + String(currTime) + ", TimerCount = " + String(TimerCount));
+}
+
+void TimerHandler(void)
+{
+  static bool toggle = false;
+
+  // Flag for checking to be sure ISR is working as SErial.print is not OK here in ISR
+  TimerCount++;
+
+  //timer interrupt toggles pin LED_BUILTIN
+  digitalWrite(LED_BUILTIN, toggle);
+  toggle = !toggle;
+}
+
+void setup()
+{
+  pinMode(LED_BUILTIN, OUTPUT);
+  
+  Serial.begin(115200);
+  while (!Serial);
+
+  delay(100);
+
+  Serial.println("\nStarting Change_Interval on " + String(BOARD_NAME));
+  Serial.println(SAMD_TIMER_INTERRUPT_VERSION);
+  Serial.println("CPU Frequency = " + String(F_CPU / 1000000) + " MHz");
+ 
+  // Interval in microsecs
+  if (ITimer.attachInterruptInterval(TIMER_INTERVAL_MS * 1000, TimerHandler))
+  {
+    Serial.println("Starting  ITimer OK, millis() = " + String(millis()));
+  }
+  else
+    Serial.println("Can't set ITimer. Select another freq. or timer");
+}
+
+#define CHECK_INTERVAL_MS     10000L
+#define CHANGE_INTERVAL_MS    20000L
+
+void loop()
+{
+  static uint32_t lastTime = 0;
+  static uint32_t lastChangeTime = 0;
+  static uint32_t currTime;
+  static uint32_t multFactor = 0;
+
+  currTime = millis();
+
+  if (currTime - lastTime > CHECK_INTERVAL_MS)
+  {
+    printResult(currTime);
+    lastTime = currTime;
+
+    if (currTime - lastChangeTime > CHANGE_INTERVAL_MS)
+    {
+      //setInterval(unsigned long interval, timerCallback callback)
+      multFactor = (multFactor + 1) % 2;
+      
+      ITimer.setInterval(TIMER_INTERVAL_MS * 1000 * (multFactor + 1), TimerHandler);
+
+      Serial.println("Changing Interval, Timer = " + String(TIMER_INTERVAL_MS * (multFactor + 1)));
+      
+      lastChangeTime = currTime;
+    }
+  }
+}

examples/ISR_16_Timers_Array/ISR_16_Timers_Array.ino

@@ -19,12 +19,13 @@
    Based on BlynkTimer.h
    Author: Volodymyr Shymanskyy
 
-   Version: 1.0.1
+   Version: 1.1.1
 
    Version Modified By   Date      Comments
    ------- -----------  ---------- -----------
    1.0.0   K Hoang      30/10/2020 Initial coding
    1.0.1   K Hoang      06/11/2020 Add complicated example ISR_16_Timers_Array using all 16 independent ISR Timers.
+   1.1.1   K.Hoang      06/12/2020 Add Change_Interval example. Bump up version to sync with other TimerInterrupt Libraries
 *****************************************************************************************************************************/
 /*
    Notes:
@@ -425,7 +426,7 @@ void setup()
   while (!Serial);
 
   Serial.println("\nStarting ISR_16_Timers_Array on " + String(BOARD_NAME));
-  Serial.println("Version : " + String(SAMD_TIMER_INTERRUPT_VERSION));
+  Serial.println(SAMD_TIMER_INTERRUPT_VERSION);
   Serial.println("CPU Frequency = " + String(F_CPU / 1000000) + " MHz");
 
   // Interval in microsecs