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Original question:

CC2652P: why ZC send a Leave request to ZED automatically?

CC2652P: System Description & Optimization for Fast CC2530 Rejoining

whong zhao
Genius 4180 points
Part Number: CC2652P
Other Parts Discussed in Thread: CC2530, Z-STACK

Tool/software:

Hello

System Overview​

My system operates in a ​high-density environment, where multiple ​CC2530 end devices​ report their power status (sending data when powered on, silent when off). The ​CC2652 coordinator​ remains always powered.

Key Challenges​

  1. ​Rejoining After Power Cycle​

    • Can a ​CC2530 device rejoin the Zigbee network​ after rebooting and resume data transmission?
    • Will the ​CC2652 coordinator​ continuously permit device joining?

  2. ​Ultra-Fast Rejoining for Real-Time Requirements​

    • The system has ​strict timing constraints.
    • How can the ​CC2530​ rejoin the network ​as fast as possible​ (<200ms) and start transmitting data immediately?
  • 0
    TI__Guru**** 219337 points

    Hello whong,

    1. I recall that stagger joining (item 12 of this E2E post) is recommended to alleviate the NWK buffer strain on the ZC

    • Yes
    • You need to establish a timer to re-enable permit periodically as Zigbee 3.0 has a condition about turning off permit join after a maximum 256 seconds without further intervention.  The permit join timer does restart automatically each time a new device joins the network.

    2. Since the Zigbee network information is saved inside of non-volatile memory, including network keys, Router devices can perform a silent rejoin as if they had never left the network. For Zigbee End Devices the pre-built Z-Stack library NWK layer handles the Beacon and Rejoin Request/Responses.  For each the application can be notified by the device state change to the expected node value.  ZEDs can attempt to shorten the corresponding *_POLL_RATE values as an attempt to quicken this process.

    Regards,
    Ryan

  • 0 in reply to Ryan Brown1
    Genius 4180 points

    Hello

    Can ZC perform  a silent rejoin，so the ZEDs Can automatically enter the network after power off and restart?Can ZEDS send data to ZC in this state?

  • +1 in reply to whong zhao
    TI__Guru**** 219337 points

    As always-on devices, ZRs can use incoming Link Status broadcasts to form associations/neighbors and build its routing table passively.  ZCs are included in this operation mode as a routing device.

    ZEDs must report to a parent and thus it has to actively check after a restart that it's previous parent is still nearby and recognizes it, or whether there is a closer ZR which would be a better candidate.  It cannot start to poll a prior parent which no longer recognizes it or is not in radio range, for this reason ZEDs perform a rejoin process.

    TI 15.4-Stack is available for Star Networks which do not require Zigbee mesh networking or the ZCL.

    Regards,
    Ryan