Zoltan Hudak / CANMsg

CAN message container. Defines "<<" and ">>" operators to simplify adding/getting data to/from a CAN message.

Dependents:   CAN_Hello EinlesenSensorabstand_digital_2 CAN_STABLE_EINSTEIN CAN_ex_STM32F103C8T6 ... more

CAN message container

In order to simplify adding/getting data to/from a CAN message the CANMsg class extends mbed's built-in CANMessage class by defining "<<" (append) and ">>" (extract) operators. Since it inherits everything from CANMessage, after importing the library into your project, you can use it instead of CANMessage without any additional modification or limitations. The usage of "<<" and ">>" operators is similar to the C++ io-streams operators.

  • Before adding data to a CANMsg object it is recommended to clear it by calling its clear() member function.
  • Then set up all the other properties (ID, type, format) as needed.
  • Finally append data one by one or combine them into a stream. The actual data length of a CAN message is automatically updated when using "<<" or ">>" operators. However, you have to make sure that the total length of data does not exceed eight bytes.

For an example of use have a look at this wiki page.

Import programCAN_Hello

Using CAN bus with (not just NUCLEO) mbed boards

Last commit 08 Feb 2019 by Zoltan Hudak

Files at this revision

API Documentation at this revision

Revision 4:5017a65ff423, committed 2019-02-05

Comitter:
hudakz
Date:
Tue Feb 05 14:50:19 2019 +0000
Parent:
3:4e42fdc0459f
Commit message:
Modified.

Changed in this revision

CANMsg.h Show annotated file Show diff for this revision Revisions of this file 
diff -r 4e42fdc0459f -r 5017a65ff423 CANMsg.h
--- a/CANMsg.h	Wed Apr 25 11:47:00 2018 +0000
+++ b/CANMsg.h	Tue Feb 05 14:50:19 2019 +0000
@@ -12,7 +12,7 @@
 
 #include "CAN.h"
 
-class CANMsg : public CANMessage
+class CANMsg : public mbed::CANMessage
 {
 public:
     /** Creates empty CAN message.
@@ -45,7 +45,6 @@
     template<class T>
     CANMsg &operator<<(const T val) {
         MBED_ASSERT(len + sizeof(T) <= 8);
-        //*reinterpret_cast<T*>(&data[len]) = val; // This used to work but now it hangs at run time.
         memcpy(&data[len], &val, sizeof(T));
         len += sizeof(T);
         return *this;
@@ -56,8 +55,14 @@
     template<class T>
     CANMsg &operator>>(T& val) {
         MBED_ASSERT(sizeof(T) <= len);
-        val = *reinterpret_cast<T*>(&data[0]);
-        len -= sizeof(T);
+        if (sizeof(T) > len) {
+            memcpy(&val, data, len);
+            len = 0;
+        }
+        else {
+            memcpy(&val, data, sizeof(T));
+            len -= sizeof(T);
+        }
         memcpy(data, data + sizeof(T), len);
         return *this;
     }