main.cpp

00001 #include "mbed.h"
00002 #include "PinDetect.h"
00003 // must import Cookbook PinDetct library into project
00004 // URL: http://mbed.org/users/AjK/libraries/PinDetect/lkyxpw
00005 
00006 DigitalOut myled(LED1);
00007 DigitalOut myled2(LED2);
00008 DigitalOut myled3(LED3);
00009 DigitalOut myled4(LED4);
00010 
00011 PinDetect pb(p8);
00012 // SPST Pushbutton debounced count demo using interrupts and callback
00013 // no external PullUp resistor needed
00014 // Pushbutton from P8 to GND.
00015 // A pb hit generates an interrupt and activates the callback function
00016 // after the switch is debounced
00017 
00018 // Global count variable
00019 int volatile count=0;
00020 
00021 // Callback routine is interrupt activated by a debounced pb hit
00022 void pb_hit_callback (void) {
00023     count++;
00024     myled4 = count & 0x01;
00025     myled3 = (count & 0x02)>>1;
00026     myled2 = (count & 0x04)>>2;
00027 }
00028 int main() {
00029 
00030     // Use internal pullup for pushbutton
00031     pb.mode(PullUp);
00032     // Delay for initial pullup to take effect
00033     wait(.01);
00034     // Setup Interrupt callback function for a pb hit
00035     pb.attach_deasserted(&pb_hit_callback);
00036     // Start sampling pb input using interrupts
00037     pb.setSampleFrequency();
00038 
00039     //Blink myled in main routine forever while responding to pb changes
00040     // via interrupts that activate the callback counter function
00041     while (1) {
00042         myled = !myled;
00043         wait(.5);
00044     }
00045 
00046 }