main.cpp

00001 /*
00002     Title:  Program to keep track of time on 4 digit display
00003     Description: This program will keep keep track of time
00004                  with initial hours minutes seconds set by
00005                  Global variables. The time is given in military format
00006 */
00007 #include "mbed.h"                       // include mbed library
00008 #include "DigitDisplay.h"               // include digit display library
00009 DigitalOut myled(LED1);                 // define myled to be internal RED led
00010 DigitDisplay display(D2,D3);            // connect digit display to D1 connector
00011 Ticker tick;                            // set up periodic interrupt called tick
00012 
00013 // Global Variables                     // initialize hour minute and second
00014 uint8_t hour   = 14;                    // same as unsigned char hour
00015 uint8_t minute = 44;                    // same as unsigned char minute
00016 uint8_t second = 0;                     // same as unsigned char second
00017 
00018 void beat()                             // periodic interrupt code
00019 {
00020     static uint8_t colon = 0;           // initialize colon to off  
00021     display.setColon(colon);            // update colon on display
00022     if (colon) 
00023     {                                   // if colon on add 1 to second
00024        second++;
00025        if (second >= 60) 
00026        {                                // if > or = 60 sec reset to 0
00027          second = 0;
00028          minute++;                      // add 1 to minute counter
00029          if (minute >= 60) 
00030             {                           // if > or = 60 then reset to 0
00031                minute = 0;
00032                hour++;                  // add 1 to hour counter
00033                if (hour >= 24)          // if > or = 24 then reset to 0
00034                    hour = 0;
00035                                         // update hour on left 2 displays
00036                 display.write(0, hour / 10);
00037                 display.write(1, hour % 10);
00038             }                           // update minute on right 2 displays
00039           display.write(2, minute / 10);
00040           display.write(3, minute % 10);
00041        }
00042     }
00043     colon = 1 - colon;                  // invert colon value
00044 }
00045 
00046 int main() 
00047 {
00048     display.write(0, hour / 10);        // put left digit of hour on left disp
00049     display.write(1, hour % 10);        // put right digit of hour on next disp
00050     display.write(2, minute / 10);      // put left digit of min on next disp
00051     display.write(3, minute % 10);      // put right digit of min on next disp
00052     display.setColon(true);             // turn colon on 
00053     tick.attach(&beat, 0.5);            // beat() activates every 0.5 seconds
00054     while(1)                            // endless loop
00055     {  
00056         myled = 1;                      // turn off red led
00057         wait(0.5);                      // wait 0.5 seconds
00058         myled = 0;                      // turn on red led
00059         wait(0.5);                      // wait 0.5 seconds
00060     }
00061 }