Diff: main.cpp

Revision:

0:faab03ae0c8a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Feb 04 23:19:25 2015 +0000
@@ -0,0 +1,86 @@
+#include "mbed.h"
+
+/*  THIS PROGRAM IS WRITTEN FOR THE FRDM-Kl25Z BUT CAN BE ADAPTED TO ANY MBED BOARD
+    
+    To use this program you need to add a bit of hardware: A single wire from "D1" to "D3." 
+    
+    
+    Here's how it works: The PWN, the interrupt, and the LED are all set up with the first three lines.
+    
+    Next, a one-line function is defined to toggle the blue LED.
+    
+    The program enters the main() program area and makes sure the blue light is turned off.
+    Yep, on this system apparently '1' means OFF and '0' means 'ON.'
+    
+    Next, the PWM parameters are set followed by the interrupt parameters
+    
+    Then, the program enters an endless while() loop with nothing in it.
+    
+    Upon reset, the PWM begins sending a steady pulse out of the PTD5 pin
+    
+    If PTD5 pulses "high" and is connected to the PTD3 pin then it triggers an interrupt which directs
+    program control to the toggler() function which toggles the blue LED, (it turns it 'ON' if it is already 'OFF'
+    or turns it 'OFF' if it is already 'ON.')
+    
+    After returning from the interrupt handling routine, toggler(), the program returns to the while() loop
+    to await the next interrupt.
+    
+    Experiment with removing the wire from PTD5 and connecting the free end to ground.
+    
+    Try changing the LED DigitalOut assignment from PTD1 to PTB19 or PTB18.
+    
+    Look up the functions and fiddle around with the PWM parameters.
+    
+    BTW, "PT" as in "PTB19" or "PTD3" stands for "PORT."  And the "D" or "B" stands for Port D or Port B.
+    The number after it is its pin number in the port.  So, PTB18 means Port B pin #18.    
+*/
+
+
+ // The PWM setup for PTD5
+ // PTD5 is the "D5" pin 
+ // on the FRDM-KL25Z
+ 
+PwmOut pulseout(PTD5);
+ 
+ // The interrupt setup for PTD3
+ // PTD3 is the "D3" pin
+ // on the FRDM-KL25Z
+InterruptIn pulsein(PTD3);
+  
+ // The LED that will be
+ // toggled to indicate
+ // an incoming pulse from
+ // the PTD5 pin to the
+ // PTD3 pin.
+ // PTD1 is the blue
+ // LED on the FRDM-KL25Z
+DigitalOut blue(PTD1);
+
+ 
+ // The LED toggling function
+void toggler(){ blue = !blue; }
+
+int main() {
+
+    blue = 1;
+    
+        // PWM pin parameters
+    pulseout.period_ms(20);     // total pulse time "OFF" and "ON".
+    pulseout.pulsewidth_ms(10); // pulse "ON" time.
+    
+        // Interrupt pin parameters
+        
+          // Pin is set to pull up
+    pulsein.mode(PullNone);
+          // Pin triggers an intertupt
+          // the rising edge and turns
+          // control over to the 
+          // function toggler().
+    pulsein.rise(&toggler); 
+    
+ // While awaiting an interrupt
+ // the program simply cycles
+ //in an empty while loop.
+while(1) {}
+}
+