v1.0.3

### Releases v1.0.3 1. Restructure code. 2. Fix example. 3. Enhance README.
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diff --git a/README.md b/README.md
@@ -6,76 +6,115 @@
 [![contributions welcome](https://img.shields.io/badge/contributions-welcome-brightgreen.svg?style=flat)](#Contributing)
 [![GitHub issues](https://img.shields.io/github/issues/khoih-prog/ESP8266TimerInterrupt.svg)](http://github.com/khoih-prog/ESP8266TimerInterrupt/issues)
 
+### Releases v1.0.3
+
+1. Restructure code.
+2. Fix example.
+3. Enhance README.
+
+### Releases v1.0.2
+
+1. Basic hardware timers for ESP8266.
+2. Fix compatibility issue causing compiler error while using Arduino IDEs before 1.8.10 and ESP8266 cores 2.5.2 and before
+3. More hardware-initiated software-enabled timers
+4. Longer time interval
+
+## Features
+
 This library enables you to use Interrupt from Hardware Timers on an ESP8266-based board.
 
-Why do we need this Hardware Timer Interrupt?
+#### Why do we need this Hardware Timer Interrupt?
 
-Imagine you have a system with a mission-critical function, measuring water level and control the sump pump 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().
+Imagine you have a system with a ***mission-critical*** function, measuring water level and control the sump pump 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.
+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 a Hardware Timer with Interrupt to call your function.
+The correct choice is to use a Hardware Timer with ***Interrupt*** to call your function.
 
-These hardware timers, using interrupt, still work even if other 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 measure some data requiring better accuracy.
+These hardware timers, using interrupt, still work even if other 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 measure some data requiring better accuracy.
 
 Functions using normal software timers, 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.
 
-The catch is your function is now part of an ISR (Interrupt Service Routine), and must be lean / mean, and follow certain rules. More to read on:
+The catch is ***your function is now part of an ISR (Interrupt Service Routine), and must be lean / mean, and follow certain rules.*** More to read on:
 
-[Attach Interrupt](https://www.arduino.cc/reference/en/language/functions/external-interrupts/attachinterrupt/)
+[Howto Attach Interrupt](https://www.arduino.cc/reference/en/language/functions/external-interrupts/attachinterrupt/)
 
-**Important Notes:**
-1. Inside the attached function, delay() won’t work and the value returned by millis() will not increment. Serial data received while in the function may be lost. You should declare as volatile any variables that you modify within the attached function.
+#### Important Notes:
+
+1. Inside the attached function, ***delay() won’t work and the value returned by millis() will not increment.*** Serial data received while in the function may be lost. You should declare as ***volatile any variables that you modify within the attached function.***
 
 2. Typically global variables are used to pass data between an ISR and the main program. To make sure variables shared between an ISR and the main program are updated correctly, declare them as volatile.
 
+## Prerequisite
+1. [`Arduino IDE 1.8.12 or later` for Arduino](https://www.arduino.cc/en/Main/Software)
+2. [`ESP8266 core 2.6.3 or later` for Arduino](https://github.com/esp8266/Arduino#installing-with-boards-manager) for ESP8266 boards.
+
 ### Installation
 
+The suggested way to install is to:
+
 #### Use Arduino Library Manager
 
-The suggested and easiest way is to use `Arduino Library Manager`. Search for `ESP8266TimerInterrupt`, then select / install the latest version.
+The best way is to use `Arduino Library Manager`. Search for `ESP8266TimerInterrupt`, then select / install the latest version. You can also use this link [![arduino-library-badge](https://www.ardu-badge.com/badge/ESP8266TimerInterrupt.svg?)](https://www.ardu-badge.com/ESP8266TimerInterrupt) for more detailed instructions.
 
 #### Manual Install
-1. Navigate to [ESP8266TimerInterrupt](https://github.com/khoih-prog/ESP8266TimerInterrupt).
+
+1. Navigate to [ESP8266TimerInterrupt](https://github.com/khoih-prog/ESP8266TimerInterrupt) page.
 2. Download the latest release `ESP8266TimerInterrupt-master.zip`.
 3. Extract the zip file to `ESP8266TimerInterrupt-master` directory 
-4. Copy whole folder to Arduino libraries' directory such as `.Arduino/libraries/ESP8266TimerInterrupt-master`.
+4. Copy whole 
+  - `ESP8266TimerInterrupt-master/src` folder to Arduino libraries' directory such as `~/Arduino/libraries/`.
+
 
 ## More useful Information
 
-The ESP8266 timers are badly designed, using only 23-bit counter along with maximum 256 prescaler. They're only better than UNO / Mega.
+The ESP8266 timers are ***badly designed***, using only 23-bit counter along with maximum 256 prescaler. They're only better than UNO / Mega.
 The ESP8266 has two hardware timers, but timer0 has been used for WiFi and it's not advisable to use. Only timer1 is available.
 The timer1's 23-bit counter terribly can count only up to 8,388,607. So the timer1 maximum interval is very short.
-Using 256 prescaler, maximum timer1 interval is only 26.843542 seconds !!!
+Using 256 prescaler, maximum timer1 interval is only ***26.843542 seconds !!!***
 
 The timer1 counters can be configured to support automatic reload.
 
 ## New from v1.0.2
 
-Now with these new `16 ISR-based timers`, the maximum interval is practically unlimited (limited only by unsigned long miliseconds)
-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.
+Now with these new ***`16 ISR-based timers`***, the maximum interval is ***practically unlimited*** (limited only by unsigned long miliseconds).
+
+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. 
 
-The `ISR_Timer_Complex` example will demonstrate the nearly perfect accuracy compared to software timers by printing the actual 
-elapsed millisecs of each type of timers.
-Being ISR-based timers, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet
-and Blynk services. You can also have many `(up to 16)` timers to use.
-This non-being-blocked important feature is absolutely necessary for mission-critical tasks. 
-You'll see blynkTimer Software is blocked while system is connecting to WiFi / Internet / Blynk, as well as by blocking task 
-in loop(), using delay() function as an example. The elapsed time then is very unaccurate
+The [ISR_Timer_Complex example](examples/ISR_Timer_Complex) will demonstrate the nearly perfect accuracy compared to software timers by printing the actual elapsed millisecs of each type of timers.
+
+Being ISR-based timers, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet and Blynk services. You can also have many `(up to 16)` timers to use. This non-being-blocked important feature is absolutely necessary for mission-critical tasks. 
+
+You'll see blynkTimer Software is blocked while system is connecting to WiFi / Internet / Blynk, as well as by blocking task in loop(), using delay() function as an example. The elapsed time then is very unaccurate
 
-## Supported Boards
+### Also see examples: 
+
+ 1. [Argument_None](examples/Argument_None)
+ 2. [ISR_RPM_Measure](examples/ISR_RPM_Measure)
+ 3. [ISR_Switch](examples/ISR_Switch) 
+ 4. [ISR_Timer_4_Switches](examples/ISR_Timer_4_Switches) 
+ 5. [ISR_Timer_Complex](examples/ISR_Timer_Complex)
+ 6. [ISR_Timer_Switch](examples/ISR_Timer_Switch)
+ 7. [ISR_Timer_Switches](examples/ISR_Timer_Switches) 
+ 8. [RPM_Measure](examples/RPM_Measure)
+ 9. [SwitchDebounce](examples/SwitchDebounce)
+10. [TimerInterruptTest](examples/TimerInterruptTest)
+
+### Supported Boards
 
 - ESP8266
 
-## Usage
+### Example [Argument_None](examples/Argument_None)
 
-How to use:
+```cpp
+#if !defined(ESP8266)
+#error This code is designed to run on ESP8266 and ESP8266-based boards! Please check your Tools->Board setting.
+#endif
 
-```
 //These define's must be placed at the beginning before #include "ESP8266TimerInterrupt.h"
 #define TIMER_INTERRUPT_DEBUG      1
 
@@ -98,58 +137,83 @@ void ICACHE_RAM_ATTR TimerHandler(void)
     pinMode(LED_BUILTIN, OUTPUT);
   }
 
-  #if (TIMER_INTERRUPT_DEBUG > 0)
-  if (lastMillis != 0)
-    Serial.println("Delta ms = " + String(millis() - lastMillis));
+#if (TIMER_INTERRUPT_DEBUG > 0)
+  Serial.println("Delta ms = " + String(millis() - lastMillis));
   lastMillis = millis();
-  #endif
-  
+#endif
+
   //timer interrupt toggles pin LED_BUILTIN
   digitalWrite(LED_BUILTIN, toggle);
   toggle = !toggle;
 }
 
-#define TIMER_INTERVAL_MS        1000 
+#define TIMER_INTERVAL_MS        1000
 
-// Init ESP8266 timer 0
+// Init ESP32 timer 0
 ESP8266Timer ITimer;
 
 
 void setup()
 {
   Serial.begin(115200);
-  Serial.println("\nStarting");
+  while (!Serial);
 
+  Serial.println("\nStarting Argument_None");
+
   // Interval in microsecs
   if (ITimer.attachInterruptInterval(TIMER_INTERVAL_MS * 1000, TimerHandler))
-    Serial.println("Starting  ITimer OK, millis() = " + String(millis()));
+  {
+    lastMillis = millis();
+    Serial.println("Starting  ITimer OK, millis() = " + String(lastMillis));
+  }
   else
     Serial.println("Can't set ITimer correctly. Select another freq. or interval");
 
 }
 
 void loop()
 {
-  
+
 }
 
 ```
-## TO DO
 
-1. Search for bug and improvement.
+### Releases v1.0.3
 
-## DONE
+1. Restructure code.
+2. Fix example.
+3. Enhance README.
 
-For current version v1.0.2
+### Releases v1.0.2
 
 1. Basic hardware timers for ESP8266.
 2. Fix compatibility issue causing compiler error while using Arduino IDEs before 1.8.10 and ESP8266 cores 2.5.2 and before
 3. More hardware-initiated software-enabled timers
 4. Longer time interval
-5. Similar features for Arduino (UNO, Mega, etc...) and ESP32
 
+### Releases v1.0.1
+
+1. Fixing compiler error
+
+### Releases v1.0.0
+
+1. Initial coding
+
+
+## TO DO
+
+1. Search for bug and improvement.
+2. Similar features for remaining Arduino boards suh as SAMD21, SAMD51, SAM-DUE, nRF52
+
+## DONE
+
+1. Similar features for Arduino (UNO, Mega, etc...) and ESP32 
+
+
+### Contributions and thanks
 
 ## Contributing
+
 If you want to contribute to this project:
 - Report bugs and errors
 - Ask for enhancements

diff --git a/examples/Argument_None/Argument_None.ino b/examples/Argument_None/Argument_None.ino
@@ -1,23 +1,52 @@
-/************************************************
- * examples/Argument_None.ino
- * For ESP8266 boards
- * Written by Khoi Hoang
- * 
- * Built by Khoi Hoang https://github.com/khoih-prog/ESP32TimerInterrupt
- * Licensed under MIT license
- * Version: v1.0.1
- * 
- * 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.
- *
- ************************************************/
+/****************************************************************************************************************************
+   Argument_None.ino
+   For ESP8266 boards
+   Written by Khoi Hoang
+
+   Built by Khoi Hoang https://github.com/khoih-prog/ESP8266TimerInterrupt
+   Licensed under MIT license
+   Version: 1.0.3
+
+   The ESP8266 timers are badly designed, using only 23-bit counter along with maximum 256 prescaler. They're only better than UNO / Mega.
+   The ESP8266 has two hardware timers, but timer0 has been used for WiFi and it's not advisable to use. Only timer1 is available.
+   The timer1's 23-bit counter terribly can count only up to 8,388,607. So the timer1 maximum interval is very short.
+   Using 256 prescaler, maximum timer1 interval is only 26.843542 seconds !!!
+
+   Now with these new 16 ISR-based timers, the maximum interval is practically unlimited (limited only by unsigned long miliseconds)
+   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 Modified By   Date      Comments
+   ------- -----------  ---------- -----------
+    1.0.0   K Hoang      23/11/2019 Initial coding
+    1.0.1   K Hoang      25/11/2019 New release fixing compiler error
+    1.0.2   K.Hoang      26/11/2019 Permit up to 16 super-long-time, super-accurate ISR-based timers to avoid being blocked
+    1.0.3   K.Hoang      17/05/2020 Restructure code. Fix example. Enhance README.
+*****************************************************************************************************************************/
+
+/* 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(ESP8266)
+#error This code is designed to run on ESP8266 and ESP8266-based boards! Please check your Tools->Board setting.
+#endif
+
 //These define's must be placed at the beginning before #include "ESP8266TimerInterrupt.h"
 #define TIMER_INTERRUPT_DEBUG      1
 
@@ -40,17 +69,17 @@ void ICACHE_RAM_ATTR TimerHandler(void)
     pinMode(LED_BUILTIN, OUTPUT);
   }
 
-  #if (TIMER_INTERRUPT_DEBUG > 0)
+#if (TIMER_INTERRUPT_DEBUG > 0)
   Serial.println("Delta ms = " + String(millis() - lastMillis));
   lastMillis = millis();
-  #endif
-  
+#endif
+
   //timer interrupt toggles pin LED_BUILTIN
   digitalWrite(LED_BUILTIN, toggle);
   toggle = !toggle;
 }
 
-#define TIMER_INTERVAL_MS        1000 
+#define TIMER_INTERVAL_MS        1000
 
 // Init ESP32 timer 0
 ESP8266Timer ITimer;
@@ -59,8 +88,10 @@ ESP8266Timer ITimer;
 void setup()
 {
   Serial.begin(115200);
-  Serial.println("\nStarting");
+  while (!Serial);
 
+  Serial.println("\nStarting Argument_None");
+
   // Interval in microsecs
   if (ITimer.attachInterruptInterval(TIMER_INTERVAL_MS * 1000, TimerHandler))
   {
@@ -74,5 +105,5 @@ void setup()
 
 void loop()
 {
-  
+
 }