Arduino 101 Curie Timer One PWM

With this tutorial you learn to use one of the timers available in the microcontroller to generate a PWM signal. The Pin selected for the signal is Pin 13 and this will blink the on-board LED. The period of the signal is 1 second (1000000 microseconds) and the duty cycle is set at 25%. The waveform generation, once started, just goes on. In the loop() you can put your code and that won't interfere with PWM signal unless you use timer functions.

Hardware Required

• Arduino 101

The Circuit

image developed using Fritzing. No additional hardware is needed to use this tutorial.

Software Essentials

Libraries

CurieTimerOne.h is the library that provides access to the Timer 1 of the microcontroller. This library allows to set up the number of microseconds that the timer counts before it asserts an interrupt. The interrupt can be configured to call a specific function - the callback function - and each interrupt increments a counter. The same library is used to generate a PWM signal with duty cycle and period length fully customizable.

Functions

None

Code

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1#include "CurieTimerOne.h"
2
3void setup() {
4
5  // Setup a PWM signal on pin 13, onboard LED, with a 25% duty cycle
6
7  // of a 1 second period (1000000 usec), as follow (please note the
8
9  // decimal point to indicate double):
10
11  CurieTimerOne.pwmStart(13, 25.0, 1000000);
12
13  // Or, use discrete number range, 0-1023, to define the duty period,
14
15  // 255 is 24.9%, as follow:
16
17  // CurieTimerOne.pwmStart(13, 255, 1000000);
18}
19
20void loop() {
21
22  // put your main code here, to run repeatedly:
23
24  delay( 10000 );
25}

Last revision 2016/03/13 by SM