CC2530: Why _NIB is used in CC2530

_NIB is used for network information storage.

of that device itself ???,
is there any time _NIB s passed from an end device to parent ??

I couldn't understand your question. Can you elaborate?

is _NIB stores its own network details in NIB

Yes

is there is any time that this NIB of end device is passed to its parent ???

No, _NIB is stored on each device and only for local usage.

if ( _NIB.nwkDevAddress == INVALID_NODE_ADDR )
{
uint16 commNwkAddr;

// Verify if the Network address has been commissioned by external tool
if ( ( osal_nv_read( ZCD_NV_COMMISSIONED_NWK_ADDR, 0,
sizeof(commNwkAddr),
(void*)&commNwkAddr ) == ZSUCCESS ) &&
( commNwkAddr != INVALID_NODE_ADDR ) )
{
_NIB.nwkDevAddress = commNwkAddr;

//clear Allocate address bit because device has a commissioned address
_NIB.CapabilityFlags &= ~CAPINFO_ALLOC_ADDR;
}
else
{
_NIB.nwkDevAddress = osal_rand();
}

ZMacSetReq( ZMacShortAddress, (byte*)&_NIB.nwkDevAddress );
}




this is section from ZDApp.c can you please explain who's NIB.nwkDevAddress is mentioned above ???

It's device's short address.

Where can i find the end device adressing process in coordinator???


Which function is used for that??

Do you mean to know detail of how coordinator assigns short address to end device?

Yes