====== ItimerSet() ======

''ItimerSet()'' sets the interval and callback function, or the hardware timer to use.

{{:en-us_commands:reference:itimerset.svg?900|ItimerSet command operation flow}}

''bool ItimerSet(unsigned long intervalMs, void (*callback)())''\\
''bool ItimerSet(uint8_t timerNumber, unsigned long intervalMs, void (*callback)())''

===== Commands =====

^ Command ^ Arguments ^ Return Value ^ Operation ^
| ''ItimerSet(intervalMs, callback)'' | ''unsigned long intervalMs'' — Callback interval in ms. ''0'' is not allowed\\ ''void (*callback)()'' — Function in ''void functionName()'' form, called at each interval | ''bool'' | Sets the interval and callback function, or the hardware timer to use. |


===== Example =====

This uses the default callback timer (Timer2). The callback changes only a flag; serial output runs in ''loop()''.

<code cpp>
volatile bool tick = false;

void onTimer() {
  tick = true;
}

void setup() {
  Serial.begin(115200);
  if (!ItimerSet(1000, onTimer)) return;  // Configure a 1 s callback on the default hardware timer.
  ItimerStart();  // Start the configured callback timer.
}

void loop() {
  if (tick) {
    noInterrupts();
    tick = false;
    interrupts();
    Serial.println(F("tick"));
  }
}
</code>

===== Precautions =====

  * The callback runs in an interrupt. Change only a flag there; do not call ''delay()'', ''Serial'', I2C or SPI in it.
  * The callback timer without a timer number uses Timer2. Do not use it together with ''tone()'' or PWM output that uses Timer2.
  * When specifying another hardware timer, check for conflicts with PWM, analog output and high-speed counter functions using it.
  * A zero interval or missing callback makes configuration fail and return false.

===== Built-in Commands in the Same Category =====

  * [[:en-us_commands:reference:itimerstart|ItimerStart() View detailed description]]
  * [[:en-us_commands:reference:itimerstop|ItimerStop() View detailed description]]
  * [[:en-us_commands:reference:itimerstopall|ItimerStopAll() View detailed description]]
  * [[:en-us_commands:reference:itimerstate|ItimerState() View detailed description]]

[[:en-us_commands:builtin|← Built-in Command List]]