University of Plymouth - Stages 1, 2 and 3 / Mbed OS Task523Solution

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

main.cpp

Committer:
noutram
Date:
2015-09-24
Revision:
0:277f12eec770
Child:
2:df9c87ac7704

File content as of revision 0:277f12eec770:

#include "mbed.h"

//Global PWM object
PwmOut pwmRed(D7);

int T = 100;    //100uS
volatile int Tmark = 0; //0us
volatile int delta = 1; //1us

//Timer
Ticker t;

//Function prototype 
void doTwinkle();

int main() {
    
    //Initial PWM state
    pwmRed.period_us(T);
    pwmRed.pulsewidth_us(Tmark);
    
    //Start timer
    t.attach(doTwinkle, 0.01);
    
    while(1) {
        sleep();
        
        //Update PWM
        pwmRed.pulsewidth_us(Tmark);
        
        //printf("Tmark = %d\n", Tmark);    //Debug
    }
}

//ISR for Timer
void doTwinkle()
{
    //Update mark time
    Tmark += delta;
    
    //Check bounds - and swap direction
    if ((Tmark >= 99) || (Tmark <= 0)) {
        delta = -delta;
    }
}