edit

Timer

CT-ARM has 4 built-in hardware timers: Timer1, Timer2, Timer3 and Timer4. These timers do not interfere with functions like delay(), delayMicroseconds(), millis() and micros(). This Timer library allows users to use timer interrupts for program routines.

Note

Tone library uses Timer2, so make sure that you do not use Timer2 interrupts with function Tone()

initialize()

Description

You must call this method first to use any of the other methods. You can optionally specify the timer's period here (in microseconds), by default it is set at 1 second.

Syntax

Timer1.initialize(period)

Also applies to Timer2, Timer3 and Timer4.

Parameters

• period: timer's period in microseconds, ranges from 2 to 16,777,216

Return

None

attachInterrupt()

Description

Calls a function at the specified time interval in microseconds. The time interval is set from initialize() function. Be careful about trying to execute too complicated of an interrupt at too high of a frequency, or the CPU may never enter the main loop and your program will 'lock up'.

Syntax

Timer1.attachInterrupt(handler)

Also applies to Timer2, Timer3 and Timer4.

Parameters

• handler: the ISR to call when the interrupt occurs; this function must take no parameters and return nothing. This function is sometimes referred to as an interrupt service routine.

Return

None

Example

void setup()
{
  pinMode(10, OUTPUT);
  Timer1.initialize(500000);         // initialize timer1, and set a 1/2 second period
  Timer1.attachInterrupt(callback);  // attaches callback() as a timer overflow interrupt
}

void callback()
{
  digitalWrite(10, digitalRead(10) ^ 1);
}

void loop()
{
  // your program here...
}

detachInterrupt()

Description

Disables the attached interrupt.

Syntax

Timer1.detachInterrupt()

Also applies to Timer2, Timer3 and Timer4.

Parameters

None

Return

None