main.cpp

00001 #include "mbed.h"
00002 
00003 DigitalOut myled(LED1);
00004 DigitalOut myled2(LED2);
00005 DigitalOut myled3(LED3);
00006 DigitalOut myled4(LED4);
00007 
00008 InterruptIn pb(p8);
00009 // SPST Pushbutton count demo using interrupts
00010 // no external PullUp resistor needed
00011 // Pushbutton from P8 to GND.
00012 // A pb hit generates an interrupt and activates the interrupt routine
00013 
00014 // Global count variable
00015 int volatile count=0;
00016 
00017 // pb Interrupt routine - is interrupt activated by a falling edge of pb input
00018 void pb_hit_interrupt (void) {
00019     count++;
00020     myled4 = count & 0x01;
00021     myled3 = (count & 0x02)>>1;
00022     myled2 = (count & 0x04)>>2;
00023 }
00024 
00025 int main() {
00026     // Use internal pullup for pushbutton
00027     pb.mode(PullUp);
00028     // Delay for initial pullup to take effect
00029     wait(.01);
00030     // Attach the address of the interrupt handler routine for pushbutton
00031     pb.fall(&pb_hit_interrupt);
00032     // Blink myled in main routine forever while responding to pb changes
00033     // via interrupts that activate pb_hit_interrupt routine
00034     while (1) {
00035         myled = !myled;
00036         wait(.5);
00037     }
00038 }