ISR_16_Timers_Array_Complex.ino

/****************************************************************************************************************************
  ISR_16_Timers_Array_Complex.ino
  For AVR ATmega164, ATmega324, ATmega644, ATmega1284 with MightyCore
  Written by Khoi Hoang

  Built by Khoi Hoang https://github.com/khoih-prog/ATmega_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.
  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.
*****************************************************************************************************************************/

// These define's must be placed at the beginning before #include "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 just 1 TIMER to be true
#define USE_TIMER_1     true
#define USE_TIMER_2     false
// TIMER_3 Only valid for ATmega1284 and ATmega324PB (not ready in core yet)
#define USE_TIMER_3     false
// TIMER_4 Only valid for ATmega324PB, not ready in core yet
#define USE_TIMER_4     false

#if USE_TIMER_1
  #define CurrentTimer   ITimer1
#elif USE_TIMER_2
  #define CurrentTimer   ITimer2
#elif USE_TIMER_3
  #define CurrentTimer   ITimer3
#elif USE_TIMER_4
  #define CurrentTimer   ITimer4
#else
  #error You must select one Timer  
#endif

#if (_TIMERINTERRUPT_LOGLEVEL_ > 3)
  #if (USE_TIMER_1)
    #warning Using Timer1  
  #elif (USE_TIMER_2)
    #warning Using Timer2
  #elif (USE_TIMER_3)
    #warning Using Timer3
  #elif (USE_TIMER_4)
    #warning Using Timer4
  #endif
#endif

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

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

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

#ifndef LED_BUILTIN
  #define LED_BUILTIN       13
#endif

ISR_Timer ISR_timer;

#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 TIMER_INTERVAL_MS            5L

volatile uint32_t startMillis = 0;

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

  ISR_timer.run();

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

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

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

#define NUMBER_ISR_TIMERS         16

typedef void (*irqCallback)  (void);

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

#define USE_COMPLEX_STRUCT      true

#if USE_COMPLEX_STRUCT

  typedef struct 
  {
    irqCallback   irqCallbackFunc;
    uint32_t      TimerInterval;
    unsigned long deltaMillis;
    unsigned long previousMillis;
  } ISRTimerData;
  
  // Avoid doing something fancy in ISR, for example Serial.print()
  // The pure simple Serial.prints here are just for demonstration and testing. Must be eliminate in working environment
  // Or you can get this run-time error / crash
  
  void doingSomething(int index);

#else

  volatile unsigned long deltaMillis    [NUMBER_ISR_TIMERS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
  volatile unsigned long previousMillis [NUMBER_ISR_TIMERS] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
  
  // You can assign any interval for any timer here, in milliseconds
  uint32_t TimerInterval[NUMBER_ISR_TIMERS] =
  {
    5000L,  10000L,  15000L,  20000L,  25000L,  30000L,  35000L,  40000L,
    45000L, 50000L,  55000L,  60000L,  65000L,  70000L,  75000L,  80000L
  };
  
  void doingSomething(int index)
  {
    unsigned long currentMillis  = millis();
    
    deltaMillis[index]    = currentMillis - previousMillis[index];
    previousMillis[index] = currentMillis;
  }

#endif

////////////////////////////////////
// Shared
////////////////////////////////////

void doingSomething0()
{
  doingSomething(0);
}

void doingSomething1()
{
  doingSomething(1);
}

void doingSomething2()
{
  doingSomething(2);
}

void doingSomething3()
{
  doingSomething(3);
}

void doingSomething4()
{
  doingSomething(4);
}

void doingSomething5()
{
  doingSomething(5);
}

void doingSomething6()
{
  doingSomething(6);
}

void doingSomething7()
{
  doingSomething(7);
}

void doingSomething8()
{
  doingSomething(8);
}

void doingSomething9()
{
  doingSomething(9);
}

void doingSomething10()
{
  doingSomething(10);
}

void doingSomething11()
{
  doingSomething(11);
}

void doingSomething12()
{
  doingSomething(12);
}

void doingSomething13()
{
  doingSomething(13);
}

void doingSomething14()
{
  doingSomething(14);
}

void doingSomething15()
{
  doingSomething(15);
}

#if USE_COMPLEX_STRUCT

  ISRTimerData curISRTimerData[NUMBER_ISR_TIMERS] =
  {
    //irqCallbackFunc, TimerInterval, deltaMillis, previousMillis
    { doingSomething0,    5000L, 0, 0 },
    { doingSomething1,   10000L, 0, 0 },
    { doingSomething2,   15000L, 0, 0 },
    { doingSomething3,   20000L, 0, 0 },
    { doingSomething4,   25000L, 0, 0 },
    { doingSomething5,   30000L, 0, 0 },
    { doingSomething6,   35000L, 0, 0 },
    { doingSomething7,   40000L, 0, 0 },
    { doingSomething8,   45000L, 0, 0 },
    { doingSomething9,   50000L, 0, 0 },
    { doingSomething10,  55000L, 0, 0 },
    { doingSomething11,  60000L, 0, 0 },
    { doingSomething12,  65000L, 0, 0 },
    { doingSomething13,  70000L, 0, 0 },
    { doingSomething14,  75000L, 0, 0 },
    { doingSomething15,  80000L, 0, 0 }
  };
  
  void doingSomething(int index)
  {
    unsigned long currentMillis  = millis();
    
    curISRTimerData[index].deltaMillis    = currentMillis - curISRTimerData[index].previousMillis;
    curISRTimerData[index].previousMillis = currentMillis;
  }

#else

  irqCallback irqCallbackFunc[NUMBER_ISR_TIMERS] =
  {
    doingSomething0,  doingSomething1,  doingSomething2,  doingSomething3,
    doingSomething4,  doingSomething5,  doingSomething6,  doingSomething7,
    doingSomething8,  doingSomething9,  doingSomething10, doingSomething11,
    doingSomething12, doingSomething13, doingSomething14, doingSomething15
  };

#endif

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


#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 : "));Serial.print(SIMPLE_TIMER_MS / 1000);
  Serial.print(F(", ms : ")); Serial.print(currMillis);
  Serial.print(F(", Dms : ")); Serial.println(currMillis - previousMillis);

  for (uint16_t i = 0; i < NUMBER_ISR_TIMERS; i++)
  {
#if USE_COMPLEX_STRUCT    
    Serial.print(F("Timer : ")); Serial.print(i);
    Serial.print(F(", programmed : ")); Serial.print(curISRTimerData[i].TimerInterval);
    Serial.print(F(", actual : ")); Serial.println(curISRTimerData[i].deltaMillis);
#else
    Serial.print(F("Timer : ")); Serial.print(i);
    Serial.print(F(", programmed : ")); Serial.print(TimerInterval[i]);
    Serial.print(F(", actual : ")); Serial.println(deltaMillis[i]);
#endif    
  }

  previousMillis = currMillis;
}

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

  Serial.begin(115200);
  while (!Serial && millis() < 5000);

  Serial.print(F("\nStarting ISR_16_Timers_Array_Complex on ")); Serial.println(BOARD_TYPE);
  Serial.println(ATMEGA_TIMER_INTERRUPT_VERSION);
  Serial.print(F("CPU Frequency = ")); Serial.print(F_CPU / 1000000); Serial.println(F(" MHz"));

  // Timer0 is already used for micros(), millis(), delay(), etc and can't be used
  // Select Timer 1-2
  // Timer 2 is 8-bit timer, only for higher frequency
  
  CurrentTimer.init();

  // Using ATmega324 with 16MHz CPU clock ,
  // For 16-bit timer 1, set frequency from 0.2385 to some KHz
  // For 8-bit timer 2 (prescaler up to 1024, set frequency from 61.5Hz to some KHz

  if (CurrentTimer.attachInterruptInterval(TIMER_INTERVAL_MS, TimerHandler))
  {
    Serial.print(F("Starting ITimer OK, millis() = ")); Serial.println(millis());
  }
  else
    Serial.println(F("Can't set ITimer. Select another freq. or timer"));
    
  //ISR_timer.setInterval(2000L, doingSomething2s);
  //ISR_timer.setInterval(5000L, doingSomething5s);

  // Just to demonstrate, don't use too many ISR Timers if not absolutely necessary
  // You can use up to 16 timer for each ISR_Timer
  for (uint16_t i = 0; i < NUMBER_ISR_TIMERS; i++)
  {
#if USE_COMPLEX_STRUCT
    curISRTimerData[i].previousMillis = startMillis;
    ISR_timer.setInterval(curISRTimerData[i].TimerInterval, curISRTimerData[i].irqCallbackFunc);
#else
    previousMillis[i] = startMillis;
    ISR_timer.setInterval(TimerInterval[i], irqCallbackFunc[i]);
#endif    
  }

  // 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();
}