ISR_Timers_Array_Simple.ino

/****************************************************************************************************************************
  ISR_Timers_Array_Simple.ino
  For Arduino megaAVR ATMEGA4809-based boards (UNO WiFi Rev2, NANO_EVERY, etc. )
  Written by Khoi Hoang

  Built by Khoi Hoang https://github.com/khoih-prog/megaAVR_TimerInterrupt
  Licensed under MIT license

  Now with we can use these new 16 ISR-based timers, while consuming only 1 hwarware Timer.
  Their independently-selected, 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.
*****************************************************************************************************************************/

#if !( defined(__AVR_ATmega4809__) || defined(ARDUINO_AVR_UNO_WIFI_REV2) || defined(ARDUINO_AVR_NANO_EVERY) || \
      defined(ARDUINO_AVR_ATmega4809) || defined(ARDUINO_AVR_ATmega4808) || defined(ARDUINO_AVR_ATmega3209) || \
      defined(ARDUINO_AVR_ATmega3208) || defined(ARDUINO_AVR_ATmega1609) || defined(ARDUINO_AVR_ATmega1608) || \
      defined(ARDUINO_AVR_ATmega809) || defined(ARDUINO_AVR_ATmega808) )
#error This is designed only for Arduino or MegaCoreX megaAVR board! Please check your Tools->Board setting
#endif

// These define's must be placed at the beginning before #include "megaAVR_TimerInterrupt.h"
// _TIMERINTERRUPT_LOGLEVEL_ from 0 to 4
// 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 USING_16MHZ     == true for  16MHz to Timer TCBx => shorter timer, but better accuracy
// Select USING_8MHZ      == true for   8MHz to Timer TCBx => shorter timer, but better accuracy
// Select USING_250KHZ    == true for 250KHz to Timer TCBx => shorter timer, but better accuracy
// Not select for default 250KHz to Timer TCBx => longer timer,  but worse accuracy
#define USING_16MHZ     true
#define USING_8MHZ      false
#define USING_250KHZ    false

#define USE_TIMER_0     false
#define USE_TIMER_1     true
#define USE_TIMER_2     false
#define USE_TIMER_3     false

// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include "megaAVR_TimerInterrupt.h"

// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include "megaAVR_ISR_Timer.h"

#include <SimpleTimer.h>              // https://github.com/jfturcot/SimpleTimer

ISR_Timer ISR_Timer1;

#ifndef LED_BUILTIN
	#define LED_BUILTIN       13
#endif

#define LED_TOGGLE_INTERVAL_MS        1000L

// You have to use longer time here if having problem because Arduino AVR clock is low, 16MHz => lower accuracy.
// Tested OK with 1ms when not much load => higher accuracy.
#define TIMER1_INTERVAL_MS            1L

volatile uint32_t startMillis = 0;

volatile uint32_t deltaMillis2s = 0;
volatile uint32_t deltaMillis5s = 0;

volatile uint32_t previousMillis2s = 0;
volatile uint32_t previousMillis5s = 0;


void TimerHandler1()
{
	static bool toggle  = false;
	static int timeRun  = 0;

	ISR_Timer1.run();

	// Toggle LED every LED_TOGGLE_INTERVAL_MS = 2000ms = 2s
	if (++timeRun == ((LED_TOGGLE_INTERVAL_MS) / TIMER1_INTERVAL_MS) )
	{
		timeRun = 0;

		//timer interrupt toggles pin LED_BUILTIN
		digitalWrite(LED_BUILTIN, toggle);
		toggle = !toggle;
	}
}

void doingSomething2s()
{
	unsigned long currentMillis  = millis();

	deltaMillis2s    = currentMillis - previousMillis2s;
	previousMillis2s = currentMillis;
}

void doingSomething5s()
{
	unsigned long currentMillis  = millis();

	deltaMillis5s    = currentMillis - previousMillis5s;
	previousMillis5s = currentMillis;
}

/////////////////////////////////////////////////

#define SIMPLE_TIMER_MS        2000L

// Init SimpleTimer
SimpleTimer simpleTimer;

// Here is software Timer, you can do somewhat fancy stuffs without many issues.
// But always avoid
// 1. Long delay() it just doing nothing and pain-without-gain wasting CPU power.Plan and design your code / strategy ahead
// 2. Very long "do", "while", "for" loops without predetermined exit time.
void simpleTimerDoingSomething2s()
{
	static unsigned long previousMillis = startMillis;

	unsigned long currMillis = millis();

	Serial.print(F("SimpleTimer : programmed "));
	Serial.print(SIMPLE_TIMER_MS);
	Serial.print(F("ms, current time ms : "));
	Serial.print(currMillis);
	Serial.print(F(", Delta ms : "));
	Serial.println(currMillis - previousMillis);

	Serial.print(F("Timer2s actual : "));
	Serial.println(deltaMillis2s);
	Serial.print(F("Timer5s actual : "));
	Serial.println(deltaMillis5s);

	previousMillis = currMillis;
}

////////////////////////////////////////////////

void setup()
{
	pinMode(LED_BUILTIN, OUTPUT);

	Serial.begin(115200);

	while (!Serial);

	Serial.print(F("\nStarting ISR_Timers_Array_Simple on "));
	Serial.println(BOARD_NAME);
	Serial.println(MEGA_AVR_TIMER_INTERRUPT_VERSION);
	Serial.print(F("CPU Frequency = "));
	Serial.print(F_CPU / 1000000);
	Serial.println(F(" MHz"));

	Serial.print(F("TCB Clock Frequency = "));

#if USING_16MHZ
	Serial.println(F("16MHz for highest accuracy"));
#elif USING_8MHZ
	Serial.println(F("8MHz for very high accuracy"));
#else
	Serial.println(F("250KHz for lower accuracy but longer time"));
#endif

	ITimer1.init();

	if (ITimer1.attachInterruptInterval(TIMER1_INTERVAL_MS, TimerHandler1))
	{
		Serial.print(F("Starting  ITimer1 OK, millis() = "));
		Serial.println(millis());
	}
	else
		Serial.println(F("Can't set ITimer1. Select another freq. or timer"));

	ISR_Timer1.setInterval(2000L, doingSomething2s);
	ISR_Timer1.setInterval(5000L, doingSomething5s);

	// You need this timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary.
	simpleTimer.setInterval(SIMPLE_TIMER_MS, simpleTimerDoingSomething2s);
}

#define BLOCKING_TIME_MS      10000L

void loop()
{
	// This unadvised blocking task is used to demonstrate the blocking effects onto the execution and accuracy to Software timer
	// You see the time elapse of ISR_Timer still accurate, whereas very unaccurate for Software Timer
	// The time elapse for 2000ms software timer now becomes 3000ms (BLOCKING_TIME_MS)
	// While that of ISR_Timer is still prefect.
	delay(BLOCKING_TIME_MS);

	// You need this Software timer for non-critical tasks. Avoid abusing ISR if not absolutely necessary
	// You don't need to and never call ISR_Timer.run() here in the loop(). It's already handled by ISR timer.
	simpleTimer.run();
}