Diff: main.cpp

Revision:

4:8b298dfada81

Parent:

3:1296e996026a

Child:

5:4dacb7b72109

--- a/main.cpp	Fri May 31 11:25:09 2013 +0000
+++ b/main.cpp	Wed Oct 02 09:40:41 2013 +0000
@@ -1,26 +1,48 @@
 #include "mbed.h"
 
-//Classes
+//Define objects
 AnalogIn    emg0(PTB0); //Analog input
 PwmOut      red(LED_RED); //PWM output
 Ticker timer;
 Serial pc(USBTX,USBRX);
 
-//Functions
+/** Looper function
+* functions used for Ticker and Timeout should be of type void <name>(void)
+* i.e. no input arguments, no output arguments.
+* if you want to change a variable that you use in other places (for example in main)
+* you will have to make that variable global in order to be able to reach it both from
+* the function called at interrupt time, and in the main function.
+* To make a variable global, define it under the includes.
+* variables that are changed in the interrupt routine (written to) should be made
+* 'volatile' to let the compiler know that those values may change outside the current context.
+* i.e.: "volatile float emg_value;" instead of "float emg_value"
+* in the example below, the variable is not re-used in the main function, and is thus declared
+* local in the looper function only.
+**/
 void looper()
 {
-        float emg_value;
-        red = emg_value = emg0;
-        pc.printf("%.6f\n",emg_value);
+    /*variable to store value in*/    
+    float emg_value;
+    /*put raw emg value both in red and in emg_value*/
+    red = emg_value = emg0.read();
+    /*send value to PC. use 6 digits precision*/
+    pc.printf("%.6f\n",emg_value);
 }
 
 int main()
 {
+    /*setup baudrate. Choose the same in your program on PC side*/
     pc.baud(115200);
+    /*set the period for the PWM to the red LED*/
     red.period_ms(2);
+    /**Here you attach the 'void looper(void)' function to the Ticker object
+    * The looper() function will be called every 0.001 seconds.
+    * Please mind that the parentheses after looper are omitted when using attach.
+    */
     timer.attach(looper, 0.001);
     while(1) //Loop
     {
-         
+      /*Empty!*/
+      /*Everything is handled by the interrupt routine now!*/
     }
 }
\ No newline at end of file