The given code defines a function `MainInit` that performs initialization...

September 4, 2025 at 09:42 AM


UINT16 MainInit(void)
{
    UINT16 Error = 0;
/*Hardware init function need to be called from the application layer*/

#ifdef SET_EEPROM_PTR
    SET_EEPROM_PTR
#endif


/* Reset application function pointer*/




    /* ECATCHANGE_START(V5.13) COE4*/
    pAPPL_CoeReadInd = NULL;
    pAPPL_CoeWriteInd = NULL;
    /* ECATCHANGE_END(V5.13) COE4*/

    pAPPL_MainLoop = NULL;

    /* initialize the EtherCAT Slave Interface */
    ECAT_Init();
    /* initialize the objects */
    COE_ObjInit();


    /*indicate that the slave stack initialization finished*/
    bInitFinished = TRUE;


    bMinCycleTimeMeasurementStarted = FALSE;
    u32CycleTimeStartValue = 0;
    u32MinCycleTimeStartValue = 0;

    u32SystemTimeReadFailure = 0;

    /* Get the System Time read failure */
    {
       UINT32 u32TimeValue = 0;
       UINT32 u32Cnt = 0;
       UINT32 u32Delta = 0;

       while (u32Cnt < 1000)
       {
           HW_EscReadDWordIsr(u32TimeValue, ESC_SYSTEMTIME_OFFSET);
           HW_EscReadDWordIsr(u32Delta, ESC_SYSTEMTIME_OFFSET);

            if (u32TimeValue <= u32Delta)
            {
                    u32Delta = u32Delta - u32TimeValue;
            }
            else
            {
                //The 32Bit timer is wrapped around
                u32Delta = u32Delta + (0xFFFFFFFF - u32TimeValue);
            }


            if (u32SystemTimeReadFailure == 0)
            {
                u32SystemTimeReadFailure = u32Delta;
            }
            else if (u32SystemTimeReadFailure > u32Delta)
            {
                u32SystemTimeReadFailure = u32Delta;
            }

          u32Cnt++;
       }
    
    }




/*Application Init need to be called from the application layer*/
     return Error;
}

The given code defines a function MainInit that performs initialization tasks for an embedded EtherCAT-based system. Let’s break down the functionality:

Declaration and Initialization of Variables:
- A UINT16 variable Error is defined and initialized to 0. This variable might be used to track if any errors occur during the initialization process.
EEPROM Pointer Configuration:
- If the macro SET_EEPROM_PTR is defined, the pointer (or function) associated with SET_EEPROM_PTR is called or set. This could be used to set up or initialize the EEPROM memory.
Reset Application Function Pointers:
- Pointers related to EtherCAT communication (pAPPL_CoeReadInd, pAPPL_CoeWriteInd) and a main loop application callback (pAPPL_MainLoop) are set to NULL to ensure they are not used inadvertently before being assigned proper functions. This is a safety measure.
EtherCAT Stack Initialization:
- An EtherCAT stack initialization function, ECAT_Init, is called, which likely sets up the EtherCAT Slave Controller (ESC) interface.
- A function COE_ObjInit is called to initialize COE (CAN application protocol over EtherCAT) objects. These are related to the protocol-level configuration.
Initialization State Flags:
- A flag bInitFinished is set to TRUE, indicating that the initialization process has completed.
- Other variables related to EtherCAT cycle timing (bMinCycleTimeMeasurementStarted, u32CycleTimeStartValue, u32MinCycleTimeStartValue) are initialized. These are likely used to measure and ensure proper EtherCAT cycle times.
- A variable u32SystemTimeReadFailure is set to 0, which seems to be used to monitor system time read reliability.
System Time Read Failure Detection:
- The function monitors and determines the minimum delta (variation) between consecutive reads of the EtherCAT ESC system time.
- A loop runs 1,000 iterations (as indicated by u32Cnt < 1000) where:
  - The system time is read using HW_EscReadDWordIsr into u32TimeValue and u32Delta.
  - If the time values wrap around due to the 32-bit timer overflow, the delta is adjusted accordingly.
  - The smallest time difference (u32SystemTimeReadFailure) is tracked across iterations and updated if a smaller value is found. This captures the minimal observable system time difference, possibly to determine precision or detect time-reading anomalies.
Return Statement:
- The function ends by returning the Error variable, which remains 0 unless modified elsewhere in the code. This indicates a successful initialization by default.

Summary:

The MainInit function initializes key components of an EtherCAT-based embedded system, including:

Hardware (EEPROM setup if applicable).
EtherCAT communication stack and protocol objects.
Setting up flags and variables for application operation.
Ensuring the system time read mechanism is functioning correctly by calculating the smallest observed delta.

It is part of a larger EtherCAT application and prepares the system for further operation by the application layer.

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