v1.6.0 to fix multiple-definitions linker error

### Releases v1.6.0

1. Fix `multiple-definitions` linker error. Drop `src_cpp` and `src_h` directories
2. Add example [multiFileProject](examples/multiFileProject) to demo for multiple-file project.
3. Add support to many more boards, such as `SAMD21E1xA`, `SAMD21G1xA` and`SAMD21J1xA`
4. Optimize library code by using `reference-passing` instead of `value-passing`
5. Update all examples
6. Update `Packages_Patches`

Author: khoih-prog

CONTRIBUTING.md

@@ -14,8 +14,8 @@ If you don't find anything, please [open a new issue](https://github.com/khoih-p
 
 Please ensure to specify the following:
 
-* Arduino IDE version (e.g. 1.8.16) or Platform.io version
-* `SAMD` Core Version (e.g. Arduino SAMD core v1.8.11, Adafruit SAMD core v1.7.5, Seeed Studio SAMD v1.8.2, Sparkfun SAMD v1.8.1)
+* Arduino IDE version (e.g. 1.8.19) or Platform.io version
+* `SAMD` Core Version (e.g. Arduino SAMD core v1.8.12, Adafruit SAMD core v1.7.7, Seeed Studio SAMD v1.8.2, Sparkfun SAMD v1.8.1)
 * Contextual information (e.g. what you were trying to achieve)
 * Simplest possible steps to reproduce
 * Anything that might be relevant in your opinion, such as:
@@ -26,10 +26,10 @@ Please ensure to specify the following:
 ### Example
 
 ```
-Arduino IDE version: 1.8.16
-Arduino SAMD Core Version 1.8.11
+Arduino IDE version: 1.8.19
+Arduino SAMD Core Version 1.8.12
 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 5.4.0-96-generic #109-Ubuntu SMP Wed Jan 12 16:49:16 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
 
 Context:
 I encountered a crash while trying to use the Timer Interrupt.

README.md

@@ -12,6 +12,7 @@
 ## Table of Contents
 
 * [Changelog](#changelog)
+  * [Releases v1.6.0](#releases-v160)
   * [Releases v1.5.0](#releases-v150)
   * [Releases v1.4.0](#releases-v140)
   * [Releases v1.3.1](#releases-v131)
@@ -27,6 +28,15 @@
 
 ## Changelog
 
+### Releases v1.6.0
+
+1. Fix `multiple-definitions` linker error. Drop `src_cpp` and `src_h` directories
+2. Add example [multiFileProject](examples/multiFileProject) to demo for multiple-file project.
+3. Add support to many more boards, such as `SAMD21E1xA`, `SAMD21G1xA` and`SAMD21J1xA`
+4. Optimize library code by using `reference-passing` instead of `value-passing`
+5. Update all examples
+6. Update `Packages_Patches`
+
 ### Releases v1.5.0
 
 1. Improve frequency precision by using float instead of ulong, Check PR [change variable period from unsigned long to float #7](https://github.com/khoih-prog/SAMD_TimerInterrupt/pull/7)

changelog.md

@@ -11,26 +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.
-  
-  Based on SimpleTimer - A timer library for Arduino.
-  Author: [email protected]
-  Copyright (c) 2010 OTTOTECNICA Italy
-  
-  Based on BlynkTimer.h
-  Author: Volodymyr Shymanskyy
-  
-  Version: 1.5.0
-
-  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
-  1.2.0   K.Hoang      08/01/2021 Add better debug feature. Optimize code and examples to reduce RAM usage
-  1.3.0   K.Hoang      02/04/2021 Add support to Sparkfun SAMD21 and SAMD51 boards
-  1.3.1   K.Hoang      09/05/2021 Fix compile error to some SAMD21-based boards
-  1.4.0   K.Hoang      02/06/2021 Fix SAMD21 rare bug caused by not fully init Prescaler
-  1.5.0   K.Hoang      08/10/2021 Improve frequency precision by using float instead of ulong
 *****************************************************************************************************************************/
 
 /*
@@ -46,10 +26,13 @@
 */
 
 #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__) )
+      || 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(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
+      || defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__)  \
+      || defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
+      || defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
+      || defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
   #error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
 #endif
 
@@ -60,6 +43,7 @@
 #define TIMER_INTERRUPT_DEBUG         0
 #define _TIMERINTERRUPT_LOGLEVEL_     0
 
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMDTimerInterrupt.h"
 
 #ifndef LED_BUILTIN

examples/Argument_None/Argument_None.ino

@@ -11,26 +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.
-  
-  Based on SimpleTimer - A timer library for Arduino.
-  Author: [email protected]
-  Copyright (c) 2010 OTTOTECNICA Italy
-  
-  Based on BlynkTimer.h
-  Author: Volodymyr Shymanskyy
-  
-  Version: 1.5.0
-
-  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
-  1.2.0   K.Hoang      08/01/2021 Add better debug feature. Optimize code and examples to reduce RAM usage
-  1.3.0   K.Hoang      02/04/2021 Add support to Sparkfun SAMD21 and SAMD51 boards
-  1.3.1   K.Hoang      09/05/2021 Fix compile error to some SAMD21-based boards
-  1.4.0   K.Hoang      02/06/2021 Fix SAMD21 rare bug caused by not fully init Prescaler
-  1.5.0   K.Hoang      08/10/2021 Improve frequency precision by using float instead of ulong
 *****************************************************************************************************************************/
 
 /*
@@ -46,10 +26,13 @@
 */
 
 #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__) )
+      || 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(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
+      || defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__)  \
+      || defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
+      || defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
+      || defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
   #error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
 #endif
 
@@ -60,6 +43,7 @@
 #define TIMER_INTERRUPT_DEBUG         0
 #define _TIMERINTERRUPT_LOGLEVEL_     0
 
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMDTimerInterrupt.h"
 
 //#ifndef LED_BUILTIN

examples/Argument_None_uS/Argument_None_uS.ino

@@ -11,26 +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.
-  
-  Based on SimpleTimer - A timer library for Arduino.
-  Author: [email protected]
-  Copyright (c) 2010 OTTOTECNICA Italy
-  
-  Based on BlynkTimer.h
-  Author: Volodymyr Shymanskyy
-  
-  Version: 1.5.0
-
-  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
-  1.2.0   K.Hoang      08/01/2021 Add better debug feature. Optimize code and examples to reduce RAM usage
-  1.3.0   K.Hoang      02/04/2021 Add support to Sparkfun SAMD21 and SAMD51 boards
-  1.3.1   K.Hoang      09/05/2021 Fix compile error to some SAMD21-based boards
-  1.4.0   K.Hoang      02/06/2021 Fix SAMD21 rare bug caused by not fully init Prescaler
-  1.5.0   K.Hoang      08/10/2021 Improve frequency precision by using float instead of ulong
 *****************************************************************************************************************************/
 
 /*
@@ -46,10 +26,13 @@
 */
 
 #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__) )
+      || 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(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
+      || defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__)  \
+      || defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
+      || defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
+      || defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
   #error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
 #endif
 
@@ -60,6 +43,7 @@
 #define TIMER_INTERRUPT_DEBUG         0
 #define _TIMERINTERRUPT_LOGLEVEL_     0
 
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMDTimerInterrupt.h"
 
 //#ifndef LED_BUILTIN

examples/Change_Interval/Change_Interval.ino

@@ -11,26 +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.
-  
-  Based on SimpleTimer - A timer library for Arduino.
-  Author: [email protected]
-  Copyright (c) 2010 OTTOTECNICA Italy
-  
-  Based on BlynkTimer.h
-  Author: Volodymyr Shymanskyy
-  
-  Version: 1.5.0
-
-  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
-  1.2.0   K.Hoang      08/01/2021 Add better debug feature. Optimize code and examples to reduce RAM usage
-  1.3.0   K.Hoang      02/04/2021 Add support to Sparkfun SAMD21 and SAMD51 boards
-  1.3.1   K.Hoang      09/05/2021 Fix compile error to some SAMD21-based boards
-  1.4.0   K.Hoang      02/06/2021 Fix SAMD21 rare bug caused by not fully init Prescaler
-  1.5.0   K.Hoang      08/10/2021 Improve frequency precision by using float instead of ulong
 *****************************************************************************************************************************/
 /*
    Notes:
@@ -62,10 +42,13 @@
 */
 
 #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__) )
+      || 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(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
+      || defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__)  \
+      || defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
+      || defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
+      || defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
   #error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
 #endif
 
@@ -76,7 +59,10 @@
 #define TIMER_INTERRUPT_DEBUG         0
 #define _TIMERINTERRUPT_LOGLEVEL_     0
 
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMDTimerInterrupt.h"
+
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMD_ISR_Timer.h"
 
 #include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer

examples/ISR_16_Timers_Array/ISR_16_Timers_Array.ino

@@ -11,26 +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.
-
-  Based on SimpleTimer - A timer library for Arduino.
-  Author: [email protected]
-  Copyright (c) 2010 OTTOTECNICA Italy
-
-  Based on BlynkTimer.h
-  Author: Volodymyr Shymanskyy
-
-  Version: 1.5.0
-
-  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
-  1.2.0   K.Hoang      08/01/2021 Add better debug feature. Optimize code and examples to reduce RAM usage
-  1.3.0   K.Hoang      02/04/2021 Add support to Sparkfun SAMD21 and SAMD51 boards
-  1.3.1   K.Hoang      09/05/2021 Fix compile error to some SAMD21-based boards
-  1.4.0   K.Hoang      02/06/2021 Fix SAMD21 rare bug caused by not fully init Prescaler
-  1.5.0   K.Hoang      08/10/2021 Improve frequency precision by using float instead of ulong
 *****************************************************************************************************************************/
 /*
    Notes:
@@ -53,11 +33,14 @@
 */
 
 #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.
+      || 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(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
+      || defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__)  \
+      || defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
+      || defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
+      || defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
+  #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"
@@ -67,7 +50,10 @@
 #define TIMER_INTERRUPT_DEBUG         0
 #define _TIMERINTERRUPT_LOGLEVEL_     0
 
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMDTimerInterrupt.h"
+
+// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
 #include "SAMD_ISR_Timer.h"
 
 #include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer