AON Event Fabric

I'm trying to capture new updates on BatMon module (voltage and temperature).
In order to do so, I want to call AONBatMonTemperatureGetDegC() and AONBatMonBatteryVoltageGet() only after an update.

I wrote the following piece of code:

void hwiFxn(UArg arg)
{
	System_printf("%d %d %d.\n", arg, AONBatMonTemperatureGetDegC(), AONBatMonBatteryVoltageGet());
}

Int main()
{
    /* Call board init functions */
    Board_initGeneral();

    /* Call BatMon enable function */
    AONBatMonEnable();

    /* Map Update Temp and Volt events */
    AONEventMcuSet(AON_EVENT_MCU_EVENT0, AON_EVENT_BATMON_TEMP);
    AONEventMcuSet(AON_EVENT_MCU_EVENT0, AON_EVENT_BATMON_VOLT);

    /* Hwi function to be called on temp and volt events */
    Hwi_create(INT_AON_PROG0, (Hwi_FuncPtr) hwiFxn, NULL, NULL);

    BIOS_start();
    return(0);
}

Unfortunately, I got some problems:

1. I don't know how to test if the hwi function is called because of real updates of BatMon temp and voltage measures.
2. When I remove AONEventMcuSet calls, my hwiFxn is still called by something which makes me think that  I misused the api.
3. The hwiFxn function is called repeatedly and another swi functions (button call back) in my code are not called...
4. I print the argument (arg) in hwiFxn and for the first two calls it values (as integer) are 0 and 1, then it is 855 (always). Where can I find the meaning of those numbers?

Thanks.