Remi Beges / Mbed 2 deprecated telemetry_demo_FRDM-TFC

A demonstration of the telemetry library (https://github.com/Overdrivr/Telemetry) to transfert to the desktop various data from the FRDM-TFC shield

Dependencies:   BufferedSerial FRDM-TFC-HBRIDGE mbed telemetry

Example of the 'Telemetry' library, a portable communication library for embedded devices.

This code fetches all the data from the Freescale Cup RC-car. It relies on a more advanced shield library that is able to read current feedback from HBridges.

The available data is the following :

  • Potentiometer 0
  • Potentiometer 1
  • 4-bit DIP switch
  • Battery level
  • current inside HBridge A
  • current inside HBridge B

You can use the Pytelemetry Command Line Interface to open plots, visualize the received data, and communicate with the car.

See https://github.com/Overdrivr/pytelemetrycli

Files at this revision

API Documentation at this revision

Revision 1:eeaf7cbb5582, committed 2016-02-22

Comitter:
Overdrivr
Date:
Mon Feb 22 21:40:09 2016 +0000
Parent:
0:4fbaf36176b6
Child:
2:9f07b14821b0
Commit message:
Updated code for new interface + added comments

Changed in this revision

FRDM-TFC.lib Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
telemetry.lib Show annotated file Show diff for this revision Revisions of this file 
--- a/FRDM-TFC.lib	Wed Feb 17 20:43:59 2016 +0000
+++ b/FRDM-TFC.lib	Mon Feb 22 21:40:09 2016 +0000
@@ -1,1 +1,1 @@
-https://developer.mbed.org/users/Overdrivr/code/FRDM-TFC-HBRIDGE/#86c5fc9a53d9
+https://developer.mbed.org/users/Overdrivr/code/FRDM-TFC-HBRIDGE/#787a9a24dbfb

--- a/main.cpp	Wed Feb 17 20:43:59 2016 +0000
+++ b/main.cpp	Mon Feb 22 21:40:09 2016 +0000
@@ -1,48 +1,93 @@
-#include "telemetry/driver.hpp"
+#include "telemetry/Telemetry.h"
 #include "FRDM-TFC/TFC.h"
 
+/*
+    Example of the 'Telemetry' library, a portable communication library for embedded devices.
+    
+    This code fetches all the data from the Freescale Cup RC-car.
+    It relies on a more advanced shield library that is able to read current feedback from HBridges.
+    
+    The available data is the following :
+    * Potentiometer 0
+    * Potentiometer 1
+    * 4-bit DIP switch
+    * Battery level
+    * current inside HBridge A
+    * current inside HBridge B
+    
+    You can use the Pytelemetry Command Line Interface to open plots, visualize the received data,
+    and communicate with the car.
+    See https://github.com/Overdrivr/pytelemetrycli
+*/
+
 struct TM_state
 {
     float throttle;
 };
 
+// Definition of the callback function
 void process(TM_state * state, TM_msg * msg);
 
 int main()
 {
+    // Init the shield
     TFC_Init();
-    TM_state state;
+    
+    // Create a Telemetry instance, running on uart at 115200 bauds
+    Telemetry tm(115200);
     
-    Telemetry tm(&state,115200);
-    tm.sub(process);
+    // 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 state;
+    state.throttle = 0.0;
+    
+    // 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, &state);
     
     Timer refresh_timer;
     refresh_timer.start();
+    
+    // Activate the engines !
     TFC_HBRIDGE_ENABLE;
+
     for( ; ; )
     {
-        if(refresh_timer.read_ms() > 100)
+        // 20 times per second, re-send data
+        if(refresh_timer.read_ms() > 50)
         {
-            tm.pub_f32("left",TFC_ReadMotorCurrent(0));
-            tm.pub_f32("right",TFC_ReadMotorCurrent(1));
+            tm.pub_f32("HBcurrentA",TFC_ReadMotorCurrent(0));
+            tm.pub_f32("HBcurrentB",TFC_ReadMotorCurrent(1));
             tm.pub_f32("pot0",TFC_ReadPot(0));
             tm.pub_f32("pot1",TFC_ReadPot(1));
+            tm.pub_f32("bat",TFC_ReadBatteryVoltage());
+            tm_pub_u8("dip",TFC_GetDIP_Switch());
             tm.pub_f32("throttle",state.throttle);
-            tm.pub_f32("bat",TFC_ReadBatteryVoltage());
             
             TFC_SetMotorPWM(state.throttle ,state.throttle);
+            // Update in order to process received data
             tm.update();
         }    
     }   
 }
 
+// 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 * state, TM_msg * msg)
 {
+    // If data type matches 'float32'
     if(msg->type == TM_float32)
     {
         float th = 0;
+        // Emplace the data into 'th'
         if(emplace_f32(msg,&th))
         {
+            // If the emplace has worked, push the value to the actual value state->throttle
+            // This way the processing is entirely safe
             state->throttle = th;   
         }
     }   

--- a/telemetry.lib	Wed Feb 17 20:43:59 2016 +0000
+++ b/telemetry.lib	Mon Feb 22 21:40:09 2016 +0000
@@ -1,1 +1,1 @@
-http://mbed.org/users/Overdrivr/code/telemetry/#b7a3ac7bcec8
+http://mbed.org/users/Overdrivr/code/telemetry/#8e3de1a314e1