Measure the width (time-wise) of an incoming pulse.

Dependencies:   dispBoB mbed PCA9635

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Show/hide line numbers counter.cpp Source File


00001 #include "mbed.h"
00002 #include "dispBoB.h"
00004 dispBoB db(p28, p27, p26);          //instantiate a dispBoB object
00005 InterruptIn trigger(p12);           //set up the trigger as an external interrupt
00006 Timer t;
00008 void up(){                          //call this on rising edge
00009     t.start();                      //start timer
00010 }
00012 void down(){                        //call this upon falling edge
00013     t.stop();                       //stop timer
00014     db.locate(0);
00015     db.printf("%06d", t.read_ms()); //print counter info to dispBoB 
00016     t.reset();                      //reset timer
00017 }
00019 int main() {
00020     trigger.mode(PullUp);           //activate internal pull up (hardware specific)
00021     db.init();                      //ALWAYS initialise dispBoB
00022     db.cls();                      
00023     trigger.rise(&up);              //attach up() to interrupt on rising edge of trigger
00024     trigger.fall(&down);            //attach down() to interrupt on falling edge of trigger
00025     db.printf("%06d", t.read_ms()); //display an initial count "000000"
00027     //To change the timebase just replace the read_ms() function with
00028     //read() for seconds and read_us() for microseconds. These use a 32bit 
00029     //int microsecond counter, so have a max time of ~30mins
00030 }