Diff: main.cpp

Revision:

2:ae67659d1fca

Parent:

1:958fbf7ad850

Child:

3:b05acad8736e

--- a/main.cpp	Wed Sep 02 12:57:47 2015 +0000
+++ b/main.cpp	Fri Sep 04 07:26:58 2015 +0000
@@ -21,24 +21,55 @@
 bool blink_green = false;
 bool blink_blue  = false;
 
+//with an enum, you can assign integer values to a name. You don't have to 
+//remember the numbers, just remember the names.
+//This is very handy if you want to use this with switch statements.
+//If you compare this to the previous version you'll see 
+//that this code is much more readable.
+
+//first part is creating a new datatype, enum blinkstate
+//second part is defining the names between {}
+//third part is creating a variable of the enum blinkstate type.
+enum blinkstates {BLINKRED,BLINKGREEN,BLINKBLUE,BLINKNONE} blink_state;
+
+ 
+ //function to flip one LED
 void flip1led(DigitalOut& led)
 {
-    led = !led;
+    led.write(!led.read());
 }
 
 void blink3Leds()
 {
-        if(blink_red)
+    //use the enum value!! This is set from the main loop.
+    switch(blink_state) {
+        case BLINKRED:
             flip1led(r_led);
-        if(blink_green)
+            g_led.write(led_off);
+            b_led.write(led_off);
+            break;
+        case BLINKGREEN:
             flip1led(g_led);
-        if(blink_blue)
-            flip1led(b_led);       
+            r_led.write(led_off);
+            b_led.write(led_off);
+            break;
+        case BLINKBLUE:
+            flip1led(b_led);
+            g_led.write(led_off);
+            r_led.write(led_off);
+            break;
+        case BLINKNONE:
+            r_led.write(led_off);
+            g_led.write(led_off);
+            b_led.write(led_off);
+            break;
+    }
 }
 
 int main()
 {
     Ticker ledtick;
+    blink_state = BLINKNONE;//initialize
     ledtick.attach(blink3Leds, period_led/2);
 
     r_led.write(led_off);
@@ -46,34 +77,21 @@
     b_led.write(led_off);
     pc.baud(baudrate);
     pc.printf("Hello World!\n");
-    
+
     while (true) {
-        if(pc.readable()) //if character available. If expresseion is non-zero, it's true
-        {
-            switch(pc.getc())    //read a character
-            {
+        if(pc.readable()) { //if character available. If expresseion is non-zero, it's true
+            switch(pc.getc()) {  //read a character
                 case 'r':
-                    blink_red = true;
-                    blink_green = false;
-                    blink_blue = false;
-                    g_led.write(led_off);
-                    b_led.write(led_off);
+                    blink_state = BLINKRED;//using the enum, we can just use the names defined above. This also makes it easier to extend functionality
                     break;
                 case 'g':
-                    blink_red = false;
-                    blink_green = true;
-                    blink_blue = false;
-                    r_led.write(led_off);
-                    b_led.write(led_off);
+                    blink_state = BLINKGREEN;
                     break;
                 case 'b':
-                    blink_red = false;
-                    blink_green = false;
-                    blink_blue = true;
-                    g_led.write(led_off);
-                    r_led.write(led_off);
+                    blink_state = BLINKBLUE;
                     break;
                 default:
+                    blink_state = BLINKNONE;
                     pc.printf("only r g b allowed.\n");
             }
         }