main.cpp

00001 //Load mbed basic function header
00002 #include "mbed.h"
00003 
00004 //Define the LEDs as a BUS 
00005 BusOut myleds(LED1, LED2, LED3, LED4);
00006 DigitalIn updown(p14);
00007 
00008 //Define a global count variable
00009 int cnt=0;
00010 bool direction=false;
00011 
00012  
00013 //Define a generic increment by X function. The functions to increment is passed as a pointer.  The increment amount is passed by value to the function
00014 void IncrementValueByX(int *value, int x) {
00015     *value+=x;
00016 } 
00017 
00018 //Define a generic  wait function using the milliseconds, wait time is passed by value.
00019 void WaitForTimeInMilliSeconds(int mseconds) {
00020     wait_ms(mseconds);
00021 }
00022 
00023 //Define a generic function to assign a nibble to a bus. The BUS is passed by reference and the value is passed 
00024 //   by value.
00025 void SetNibbleBusOut(BusOut *nibble,int value) {
00026        nibble->write(value & 0xF);
00027 }
00028 
00029 //Determine if a button has been released
00030 bool CheckButtonRelease(int *buttonState,DigitalIn *inputPin) {
00031     int currentButton;
00032     bool retValue;
00033      
00034      currentButton=inputPin->read();
00035      if( *buttonState != currentButton && currentButton == 0) {
00036         retValue=true;
00037      } else {
00038         retValue=false;
00039      }
00040      *buttonState=currentButton; 
00041      return retValue;
00042 }
00043 
00044 //Invert a boolean based on a boolean value.
00045 void InvertBoolBasedonValue(bool *direction, int buttonRelease){
00046    if(buttonRelease)
00047       *direction= !*direction;
00048 }
00049 
00050 //Change a boolean value based on button release
00051 void ChangeDirectionOnButtonRelease(bool *direction, DigitalIn *inputPin){
00052     bool buttonRelease=0;
00053     static int buttonState;
00054     
00055     buttonRelease=CheckButtonRelease(&buttonState,inputPin);
00056     InvertBoolBasedonValue(direction,buttonRelease);
00057 }
00058 
00059 
00060 //Main loop
00061 int main() {
00062     while(true) {
00063             ChangeDirectionOnButtonRelease(&direction,&updown);       
00064             if(direction) {
00065                IncrementValueByX(&cnt,1);
00066             } else {
00067                IncrementValueByX(&cnt,-1);
00068             }
00069             SetNibbleBusOut(&myleds,cnt);
00070             WaitForTimeInMilliSeconds(1000);
00071     }
00072 }