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

Diff: CANMsg.h

Revision:
2:2b8425b12d05
Parent:
1:34738eb16cf7
Child:
3:4e42fdc0459f
--- a/CANMsg.h	Sat Mar 18 23:09:30 2017 +0000
+++ b/CANMsg.h	Thu Mar 29 18:56:19 2018 +0000
@@ -44,32 +44,20 @@
      */
     template<class T>
     CANMsg &operator<<(const T val) {
-        if(len + sizeof(T) <= 8) {
-            *reinterpret_cast < T * > (&data[len]) = val;
-            len += sizeof(T);
-        }
-#if DEBUG
-        else {
-            printf("Error: Cannot append data - exceeding CAN data length!\r\n");
-        }
-#endif
-       return *this;
+        MBED_ASSERT(len + sizeof(T) <= 8);
+        *reinterpret_cast<T*>(&data[len]) = val;
+        len += sizeof(T);
+        return *this;
     }
 
     /** Extract operator: Extracts data (value) from CAN message
      */
     template<class T>
     CANMsg &operator>>(T& val) {
-        if(sizeof(T) <= len) {
-            val = *reinterpret_cast < T * > (&data[0]);
-            len -= sizeof(T);
-            memcpy(data, data + sizeof(T), len);
-        }
-#if DEBUG
-        else {
-            printf("Error: Cannot extract data - exceeding CAN data length!\r\n");
-        }
-#endif
+        MBED_ASSERT(sizeof(T) <= len);
+        val = *reinterpret_cast<T*>(&data[0]);
+        len -= sizeof(T);
+        memcpy(data, data + sizeof(T), len);
         return *this;
     }
 };