Fix Codespell complaints

Author: khoih-prog

README.md

@@ -92,7 +92,7 @@ This library enables you to use Interrupt from Hardware Timers on an ESP8266-bas
 
 As **Hardware Timers are rare, and very precious assets** of any board, this library now enables you to use up to **16 ISR-based Timers, while consuming only 1 Hardware Timer**. Timers' interval is very long (**ulong millisecs**).
 
-Now with these new **16 ISR-based timers**, the maximum interval is **practically unlimited** (limited only by unsigned long miliseconds) while **the accuracy is nearly perfect** compared to software timers. 
+Now with these new **16 ISR-based timers**, the maximum interval is **practically unlimited** (limited only by unsigned long milliseconds) while **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. 
 
@@ -235,7 +235,7 @@ The timer1 counters can be configured to support automatic reload.
 
 ---
 
-Now with these new **`16 ISR-based timers`**, the maximum interval is **practically unlimited** (limited only by unsigned long miliseconds).
+Now with these new **`16 ISR-based timers`**, the maximum interval is **practically unlimited** (limited only by unsigned long milliseconds).
 
 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.
 

examples/Argument_None/Argument_None.ino

@@ -1,29 +1,23 @@
 /****************************************************************************************************************************
   Argument_None.ino
-  For ESP32, ESP32_S2, ESP32_S3, ESP32_C3 boards with ESP32 core v2.0.2+
+  For ESP8266 boards
   Written by Khoi Hoang
 
-  Built by Khoi Hoang https://github.com/khoih-prog/ESP32TimerInterrupt
+  Built by Khoi Hoang https://github.com/khoih-prog/ESP8266TimerInterrupt
   Licensed under MIT license
 
-  The ESP32, ESP32_S2, ESP32_S3, ESP32_C3 have two timer groups, TIMER_GROUP_0 and TIMER_GROUP_1
-  1) each group of ESP32, ESP32_S2, ESP32_S3 has two general purpose hardware timers, TIMER_0 and TIMER_1
-  2) each group of ESP32_C3 has ony one general purpose hardware timer, TIMER_0
+  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 !!!
 
-  All the timers are based on 64-bit counters (except 54-bit counter for ESP32_S3 counter) and 16 bit prescalers.
-  The timer counters can be configured to count up or down and support automatic reload and software reload.
-  They can also generate alarms when they reach a specific value, defined by the software.
-  The value of the counter can be read by the software program.
-
-  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 ESP32-S2 timer and avoid conflicting with other cores' tasks.
+  Now with these new 16 ISR-based timers, the maximum interval is practically unlimited (limited only by unsigned long milliseconds)
   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.
 *****************************************************************************************************************************/
 
-/*
-   Notes:
+/* 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,
@@ -34,106 +28,83 @@
    or the entire sequence of your code which accesses the data.
 */
 
-#if !defined( ESP32 )
-	#error This code is intended to run on the ESP32 platform! Please check your Tools->Board setting.
+#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 "_TIMERINTERRUPT_LOGLEVEL_.h"
+// These define's must be placed at the beginning before #include "ESP8266TimerInterrupt.h"
 // _TIMERINTERRUPT_LOGLEVEL_ from 0 to 4
-#define _TIMERINTERRUPT_LOGLEVEL_     3
-
-// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
-#include "ESP32TimerInterrupt.h"
-
-// Don't use PIN_D1 in core v2.0.0 and v2.0.1. Check https://github.com/espressif/arduino-esp32/issues/5868
-// Don't use PIN_D2 with ESP32_C3 (crash)
-#define PIN_D19             19        // Pin D19 mapped to pin GPIO9 of ESP32
-#define PIN_D3               3        // Pin D3 mapped to pin GPIO3/RX0 of ESP32
+// Don't define _TIMERINTERRUPT_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system.
+#define TIMER_INTERRUPT_DEBUG         0
+#define _TIMERINTERRUPT_LOGLEVEL_     0
 
+// Select a Timer Clock
+#define USING_TIM_DIV1                false           // for shortest and most accurate timer
+#define USING_TIM_DIV16               false           // for medium time and medium accurate timer
+#define USING_TIM_DIV256              true            // for longest timer but least accurate. Default
 
-// With core v2.0.0+, you can't use Serial.print/println in ISR or crash.
-// and you can't use float calculation inside ISR
-// Only OK in core v1.0.6-
-bool IRAM_ATTR TimerHandler0(void * timerNo)
-{
-	static bool toggle0 = false;
+#include "ESP8266TimerInterrupt.h"
 
-	//timer interrupt toggles pin PIN_D19
-  digitalWrite(PIN_D19, toggle0);
-	toggle0 = !toggle0;
+#ifndef LED_BUILTIN
+  #define LED_BUILTIN       2         // Pin D4 mapped to pin GPIO2/TXD1 of ESP8266, NodeMCU and WeMoS, control on-board LED
+#endif
 
-	return true;
-}
+volatile uint32_t lastMillis = 0;
 
-// With core v2.0.0+, you can't use Serial.print/println in ISR or crash.
-// and you can't use float calculation inside ISR
-// Only OK in core v1.0.6-
-bool IRAM_ATTR TimerHandler1(void * timerNo)
+void IRAM_ATTR TimerHandler()
 {
-	/////////////////////////////////////////////////////////
-
-	static bool toggle1 = false;
-
-	//timer interrupt toggles outputPin
-	digitalWrite(PIN_D3, toggle1);
-	toggle1 = !toggle1;
+  static bool toggle = false;
+  static bool started = false;
+
+  if (!started)
+  {
+    started = true;
+    pinMode(LED_BUILTIN, OUTPUT);
+  }
+
+#if (TIMER_INTERRUPT_DEBUG > 0)
+  Serial.print("Delta ms = ");
+  Serial.println(millis() - lastMillis);
+  lastMillis = millis();
+#endif
 
-	return true;
+  //timer interrupt toggles pin LED_BUILTIN
+  digitalWrite(LED_BUILTIN, toggle);
+  toggle = !toggle;
 }
 
-#define TIMER0_INTERVAL_MS        100
+#define TIMER_INTERVAL_MS        1000
 
-#define TIMER1_INTERVAL_MS        5000
-
-// Init ESP32 timer 0 and 1
-ESP32Timer ITimer0(0);
-ESP32Timer ITimer1(1);
+// Init ESP8266 timer 1
+ESP8266Timer ITimer;
 
 void setup()
 {
-  pinMode(PIN_D19, OUTPUT);
-	pinMode(PIN_D3,  OUTPUT);
-
-	Serial.begin(115200);
+  Serial.begin(115200);
 
-	while (!Serial && millis() < 5000);
+  while (!Serial && millis() < 5000);
 
   delay(500);
 
-	Serial.print(F("\nStarting Argument_None on "));
-	Serial.println(ARDUINO_BOARD);
-	Serial.println(ESP32_TIMER_INTERRUPT_VERSION);
-	Serial.print(F("CPU Frequency = "));
-	Serial.print(F_CPU / 1000000);
-	Serial.println(F(" MHz"));
-
-	// Using ESP32  => 80 / 160 / 240MHz CPU clock ,
-	// For 64-bit timer counter
-	// For 16-bit timer prescaler up to 1024
-
-	// Interval in microsecs
-	if (ITimer0.attachInterruptInterval(TIMER0_INTERVAL_MS * 1000, TimerHandler0))
-		//if (ITimer0.attachInterrupt(1, TimerHandler0))
-	{
-		Serial.print(F("Starting  ITimer0 OK, millis() = "));
-		Serial.println(millis());
-	}
-	else
-		Serial.println(F("Can't set ITimer0. Select another Timer, freq. or timer"));
-
-
-	// Interval in microsecs
-	if (ITimer1.attachInterruptInterval(TIMER1_INTERVAL_MS * 1000, TimerHandler1))
-		//if (ITimer1.attachInterrupt(2, TimerHandler1))
-	{
-		Serial.print(F("Starting  ITimer1 OK, millis() = "));
-		Serial.println(millis());
-	}
-	else
-		Serial.println(F("Can't set ITimer1. Select another Timer, freq. or timer"));
+  Serial.print(F("\nStarting Argument_None on "));
+  Serial.println(ARDUINO_BOARD);
+  Serial.println(ESP8266_TIMER_INTERRUPT_VERSION);
+  Serial.print(F("CPU Frequency = "));
+  Serial.print(F_CPU / 1000000);
+  Serial.println(F(" MHz"));
+
+  // Interval in microsecs
+  if (ITimer.attachInterruptInterval(TIMER_INTERVAL_MS * 1000, TimerHandler))
+  {
+    lastMillis = millis();
+    Serial.print(F("Starting  ITimer OK, millis() = "));
+    Serial.println(lastMillis);
+  }
+  else
+    Serial.println(F("Can't set ITimer correctly. Select another freq. or interval"));
 }
 
 void loop()
 {
-	delay(1);
+
 }