Diff: main.cpp

Revision:

1:e0b028efe6db

Parent:

0:20e070e8ecca

--- a/main.cpp	Sat Feb 08 05:56:25 2014 +0000
+++ b/main.cpp	Sat Sep 26 20:58:40 2020 +0000
@@ -1,54 +1,61 @@
-#include "mbed.h"
-#include "DigitDisplay.h"
-
-DigitalOut myled(LED1);
-
-DigitDisplay display(P1_14, P1_13);
+/*
+    Title:  Program to keep track of time on 4 digit display
+    Description: This program will keep keep track of time
+                 with initial hours minutes seconds set by
+                 Global variables. The time is given in military format
+*/
+#include "mbed.h"                       // include mbed library
+#include "DigitDisplay.h"               // include digit display library
+DigitalOut myled(LED1);                 // define myled to be internal RED led
+DigitDisplay display(D2,D3);            // connect digit display to D1 connector
+Ticker tick;                            // set up periodic interrupt called tick
 
-Ticker tick;
+// Global Variables                     // initialize hour minute and second
+uint8_t hour   = 14;                    // same as unsigned char hour
+uint8_t minute = 44;                    // same as unsigned char minute
+uint8_t second = 0;                     // same as unsigned char second
 
-uint8_t hour   = 20;
-uint8_t minute = 14;
-uint8_t second = 0;
-
-void beat()
+void beat()                             // periodic interrupt code
 {
-    static uint8_t colon = 0;
-    
-    display.setColon(colon);
-    if (colon) {
-        second++;
-        if (second >= 60) {
-            second = 0;
-            minute++;
-            if (minute >= 60) {
-                minute = 0;
-                
-                hour++;
-                if (hour >= 24) {
-                    hour = 0;
-                }
+    static uint8_t colon = 0;           // initialize colon to off  
+    display.setColon(colon);            // update colon on display
+    if (colon) 
+    {                                   // if colon on add 1 to second
+       second++;
+       if (second >= 60) 
+       {                                // if > or = 60 sec reset to 0
+         second = 0;
+         minute++;                      // add 1 to minute counter
+         if (minute >= 60) 
+            {                           // if > or = 60 then reset to 0
+               minute = 0;
+               hour++;                  // add 1 to hour counter
+               if (hour >= 24)          // if > or = 24 then reset to 0
+                   hour = 0;
+                                        // update hour on left 2 displays
                 display.write(0, hour / 10);
                 display.write(1, hour % 10);
-            }
-            display.write(2, minute / 10);
-            display.write(3, minute % 10);
-        }
+            }                           // update minute on right 2 displays
+          display.write(2, minute / 10);
+          display.write(3, minute % 10);
+       }
     }
-    colon = 1 - colon;
+    colon = 1 - colon;                  // invert colon value
 }
 
-int main() {
-    display.write(0, hour / 10);
-    display.write(1, hour % 10);
-    display.write(2, minute / 10);
-    display.write(3, minute % 10);
-    display.setColon(true);
-    tick.attach(&beat, 0.5);
-    while(1) {
-        myled = 1;
-        wait(0.5);
-        myled = 0;
-        wait(0.5);
+int main() 
+{
+    display.write(0, hour / 10);        // put left digit of hour on left disp
+    display.write(1, hour % 10);        // put right digit of hour on next disp
+    display.write(2, minute / 10);      // put left digit of min on next disp
+    display.write(3, minute % 10);      // put right digit of min on next disp
+    display.setColon(true);             // turn colon on 
+    tick.attach(&beat, 0.5);            // beat() activates every 0.5 seconds
+    while(1)                            // endless loop
+    {  
+        myled = 1;                      // turn off red led
+        wait(0.5);                      // wait 0.5 seconds
+        myled = 0;                      // turn on red led
+        wait(0.5);                      // wait 0.5 seconds
     }
 }