Diff: main.cpp

Revision:

1:5a07069e17b6

Parent:

0:c5e974040f21

Child:

2:74d5233b6284

--- a/main.cpp	Tue Feb 16 20:33:33 2016 +0000
+++ b/main.cpp	Mon Feb 22 21:24:52 2016 +0000
@@ -1,6 +1,19 @@
 #include "mbed.h"
 #include "FRDM-TFC/TFC.h"
-#include "telemetry/driver.hpp"
+#include "telemetry/Telemetry.h"
+
+/*
+    Example of the 'Telemetry' library, a portable communication library for embedded devices.
+    The PC-side of this code is hosted a github.com/Overdrivr/telemetry-examples
+    
+    This code uses the car from the Freescale Cup competition initially dedicated to be a 
+    line-following racing car, and turns it into a full-blown radio-controlled car.
+    
+    It is using a Bluetooth serial module to provide wireless connectivity. See the repository at
+    github.com/Overdrivr/telemetry-examples for complete instructions on wiring everthing together.
+    
+    Repo : TO BE DONE  
+*/
 
 DigitalOut led(LED1);
 
@@ -9,20 +22,32 @@
   float throttle;  
 };
 
+// Definition of the callback function
 void process(TM_state* carState, TM_msg* msg);
 
 int main()
 {   
+    // Create a Telemetry instance, running on uart at 115200 bauds
+    Telemetry TM(115200);
+    
+    // a data structure to hold writeable parameters
+    // i.e. the car direction and throttle that will be both be controlled from the laptop
     TM_state carState;
     carState.direction = 0;
     carState.throttle = 0;
-    Telemetry TM(&carState);
-    TM.sub(process);
+    
+    // Suscribe our custom processing function (= callback function), and pass the data structure
+    // so that we can access it inside
+    // This way, everytime a frame is received, Telemetry will call this function for us,
+    // and pass the TM_state data structure to it.
+    TM.sub(process, &carState);
     
     led = 1;
-
+    
+    // Init the TheFreescaleCup shield
     TFC_Init();
     
+    // Some timers... for timing :p
     Timer servo_timer;
     Timer motor_timer;
     Timer tm_timer;
@@ -32,7 +57,10 @@
     motor_timer.start();
     tm_timer.start();
     print_timer.start();
+    
+    // Activate the engines !
     TFC_HBRIDGE_ENABLE;
+    
     for(;;)
     {       
         // update telemetry
@@ -60,20 +88,28 @@
         if(print_timer.read_ms() > 500)
         {
             print_timer.reset();
-            TM.pub_f32("direction",carState.direction);
+            // Publish the car parameters, so we can access them from the computer
+            TM.pub_f32("direction",carState.direction); 
             TM.pub_f32("throttle",carState.throttle);
-            led = (led == 0) ? 1 : 0;  
+            led = (led == 0) ? 1 : 0;  // Toggle the led
         }
     }
 }
 
+// This is our processing function called every time a frame is received
+// First parameter is a pointer to the data structure we defined in main
+// Second parameter is a pointer to a data structure containing all info about received frame 
 void process(TM_state* carState, TM_msg* msg)
 {
+    // temp variable
     float value = 0.f;
+    // If received topic == 'direction'
     if(strcmp(msg->topic,"direction") == 0)
     {
+        // If data type matches 'float32'
         if(emplace_f32(msg,&value))
         {
+            // Check values in order to avoid going beyond servomotor limits
             if(value > 1.f)
                 value = 1.f;
             if(value < -1.f)
@@ -81,6 +117,7 @@
             carState->direction = value;
         }
     }
+    // Idem for throttle
     else if(strcmp(msg->topic,"throttle") == 0)
     {
         if(emplace_f32(msg,&value))