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CShac
Associate III
February 14, 2019
Solved

Following a ReqRN request (to obtain the handle) 4 bytes are received. Can Anyone tell me what those 4 bytes are? Or where in those 4 bytes the handle in located? TIA

  • February 14, 2019
  • 2 replies
  • 1046 views

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    This topic has been closed for replies.
    Best answer by Bart Herse

    Hello Chris,

    did you send the Req_RN command while the tag was in the Acknowledged state? Note: if the Req_RN is not sent within the T2 timing constraint the tag will leave the Acknowledged state and return to the Arbitrate state. Please check the required timing constraints and the tag state diagram in the Gen2V2 spec.

    Cheers,

    B

    2 replies

    Bart Herse
    Visitor II
    February 14, 2019

    Hello Andrew,

    the first two bytes are the Handle/RN16 and the remaining bytes are CRC-16. Please check the Gen2V2 spec. or the ISO18000-63 standard.

    Cheers,

    B

    CShac
    CShacAuthor
    Associate III
    February 19, 2019

    Hi Bart,

    Further to my question. I seem unable to ever retrieve an RN and matching CRC when using the REQ_Rn Direct command. The Rx length register is set up to receive 4 bytes and an EPC code has been successfully read prior to the Direct Command 9Fh being issued

    Bart Herse
    Bart HerseBest answer
    Visitor II
    February 20, 2019

    Hello Chris,

    did you send the Req_RN command while the tag was in the Acknowledged state? Note: if the Req_RN is not sent within the T2 timing constraint the tag will leave the Acknowledged state and return to the Arbitrate state. Please check the required timing constraints and the tag state diagram in the Gen2V2 spec.

    Cheers,

    B

    CShac
    CShacAuthor
    Associate III
    February 14, 2019

    Many thanks. I assumed as much however it seems sometimes the CRC is not valid, but that ok I can work with that.