main.cpp

00001  // My first program did not have an interrupt and as a result sometime it would
00002  // display the button twice. this was resolved by the use on an interrupt.
00003  //     A hardware option to control debouncing would be the use of a capacitor
00004  // this will allow for a smooth switch. For a software solution an interrupt is
00005  // used for debouncing.
00006  
00007  #include "mbed.h"
00008 Serial pc (USBTX, USBRX);
00009 
00010 InterruptIn center(p14);
00011 InterruptIn left(p13);
00012 InterruptIn right(p16);
00013 InterruptIn up(p15);
00014 InterruptIn down(p12);
00015 
00016 void center_released() { wait (0.25);
00017 }
00018 void center_pressed() {
00019     pc.printf("center\n\r");
00020 }
00021 void left_released() { wait (0.25);
00022 }   
00023 void left_pressed() {
00024     pc.printf("left\n\r");
00025 }
00026 void right_released() { wait (0.25);
00027 }
00028 void right_pressed() {
00029     pc.printf("right\n\r");
00030 }
00031 void up_released() { wait (0.25);
00032 }
00033 void up_pressed() {
00034     pc.printf("up\n\r");
00035 }
00036 void down_released() { wait (0.25);
00037 }
00038 void down_pressed() {
00039     pc.printf("down\n\r");
00040 }
00041 int main() {
00042  
00043     // Both rise and fall edges generate an interrupt
00044     center.fall(&center_released);
00045     center.rise(&center_pressed);
00046     left.fall(&left_released);
00047     left.rise(&left_pressed);
00048     right.fall(&right_released);
00049     right.rise(&right_pressed);
00050     up.fall(&up_released);
00051     up.rise(&up_pressed);
00052     down.fall(&down_released);
00053     down.rise(&down_pressed);
00054    
00055     left.mode(PullDown);
00056     right.mode(PullDown);
00057     up.mode(PullDown);
00058     down.mode(PullDown);
00059    
00060     while (1) {     
00061     }
00062 }