Simple, cooperative timed tasks in Arduino

simple_time_based_cooperative.ino

/*
* Simple, cooperative timed tasks example in Arduino
* by Mark Peter Vargha
* varghamarkpeter.hu
*/

#define INTERVAL_LED 1000
#define INTERVAL_PRINT 5000

unsigned long ledTimestamp = 0;
unsigned long printTimestamp = 0;

void toggleLed()
{
    digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
}

void printElapsed()
{
    Serial.print("Elapsed time: ");
    Serial.print((millis() / 1000), DEC);
    Serial.println();
}

void setup()
{
    Serial.begin(9600);
    pinMode(LED_BUILTIN, OUTPUT);
}

void loop()
{
    if ( millis() - ledTimestamp >= INTERVAL_LED)
    {
        toggleLed();
        ledTimestamp = millis();
    }
    if (millis() - printTimestamp >= INTERVAL_PRINT)
    {
        printElapsed();
        printTimestamp = millis();
    }
}