Reference for Wiring version 0027+ If you have a previous version, use the reference includede with your software. If see any errors or have any comments, let us know.
| Class | Timer2 |
|---|---|
| Name | stop() |
| Examples | #include "HardwareTimer2.h";
int ledPin = 48; // onboard LED on the Wiring I/O board (pin 48)
byte value = HIGH;
void setup()
{
pinMode(ledPin, OUTPUT); // sets the digital pin as output
// sets Timer2 to execute function ledFlash() every 100ms
Timer2.set(100, ledFlash);
// sets Timer2 to execute function ledFlash() using timer prescaler 1024
// F_CPU / 1024 in a 16Mhz will be 15625
// 15625 / 255 = 61.27 overflows (full countings to 255)
// 1000ms / 61.27 = 16.32ms, so function ledFlash() will be executed every 16.32ms
//Timer2.set(ledFlash, CLOCK_DIV1024);
// start timer
Timer2.start();
}
void loop()
{
}
void ledFlash() {
digitalWrite(ledPin, value);
if(value == HIGH)
value = LOW;
else
value = HIGH;
} |
| Description | Timer2 is an 8-bit hardware timer present in many Atmel microcontrollers. A hardware timer might be used among other things to clock events. The Timer2 library allows for flexible manipulation of this hardware timer. The timer can be set to execute a function every certain milliseconds, a difference with setting up a software timer is the precision. Timer2 clock source is the main CPU clock which runs at 16Mhz F_CPU = 16000000, this frequency might be too fast for many uses, (1/16000000) of a second, so a prescaler is used for the clock source. A prescaler is the cpu speed divided by some power of 2. There are some prescalers defined for Timer2: CLOCK_DIV1, CLOCK_DIV8, CLOCK_DIV32, CLOCK_DIV64, CLOCK_DIV128, CLOCK_DIV256 and CLOCK_DIV1024, which are respectively F_CPU/1, F_CPU/8, F_CPU/32, F_CPU/128, F_CPU/256 and F_CPU/1024. For flexibility, Timer2 can be set in two ways, one to execute a function every certain milliseconds and the second to execute a function at a frequency defined by a prescaler. Depending on the hardware, some prescalers for Timer2 might not be available, for example for the atmega128 microcontroller the prescalers CLOCK_DIV32 and CLOCK_DIV128 are not defined, but they are defined for Timer2 on atmega1281 and atmega2561. Since Timer2 is an 8-bit timer internally it overflows when its counter TCNT2 reaches the value 255. The stop() method stops Timer2. |
| Syntax | Timer2.stop() |
| Returns | None |
| Usage | Application |
