Initialisation Process

The J1939 protocol stack is initialized with J1939_MgrInit(). This routine will setup the CAN controller and initialize all necessary services. Afterwards the stack can be started by calling the J1939_MgrStart() function.

In summary four steps are necessary to run the J1939 protocol stack:

• Initialize J1939 protocol stack: J1939_MgrInit()
• Add a PGN list to the protocol stack: J1939_PgnAddList()
• Start J1939 protocol stack: J1939_MgrStart()
• Call the timer event function cyclically: J1939_TmrEvent()

The initialization functions of the J1939 protocol stack have to be executed prior to any other API functions.

Initialization of J1939 protocol stack

void MyJ1939_Init(void)
{
   //-----------------------------------------------------------------------------------------
   // Initialize the J1939 protocol stack:
   // Assign logical J1939 net 1 to physical CAN interface 1, use ECU address 2
   //
   J1939_MgrInit(eCP_CHANNEL_1, eJ1939_NET_1, 2, J1939_CONF_BITRATE_250K);   
 
   //-----------------------------------------------------------------------------------------
   // Add a PGN list to the logical network 1, use ECU1 PGN list in this example
   //
   J1939_PgnAddList(eJ1939_NET_1, &atsPgnListEcu1[0]);
 
   //-----------------------------------------------------------------------------------------
   // Start the J1939 protocol stack
   //
   J1939_MgrStart(eJ1939_NET_1);
   
   //-----------------------------------------------------------------------------------------
   // Now the J1939 protocol stack is started and has to be triggered by calling 
   // J1939_TmrEvent() with a cycle time of J1939_TIMER_PERIOD.
   // We initialize the timer resource on the target CPU and call J1939_TmrEvent() with an
   // update rate of 1 ms here
   //
   McTmrInit();
   McTmrFunctionInit(J1939_TmrEvent, McTmrTimeToTicks(1000), eTMR_CTRL_START);
}

After calling J1939_MgrStart() the J1939 Protocol Stack is running and an Address Claiming Message (ACM) is send on the CAN bus (i.e. the identifier 18EEFF00_h + ECU-address).