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TRF7970A:

shivu ns1
Prodigy 110 points
Part Number: TRF7970A

Hello ,

we designed coil antenna for NFC , for that my present Bandwidth is around 1Mhz (fC=13.70MHz) but detection of some cards was not happening. so kindly suggest me   what is exact band width of antenna will detect all cards (master , visa)and mobiles. 

Thanks and regards,

Shivu

  • 0
    TI__Guru*** 135355 points

    Hello Shivu,

    You will want the broader bandwidth for ISO14443A technology tags which is achieved with a Q around 7-8. Usually that is about 1.7MHz-2MHz. 1MHz bandwidth is probably too narrow.

    Some tags are off tuned to higher frequencies to reduce read range intentionally as well, make sure you are trying at short read ranges for hard to read tags in addition. But those sorts of tags would also be significantly harder to read without the extra bandwidth (I've seen them tuned to 14.5-15MHz before).

    You need to make sure the form factor lines up somewhat with the tags you want to read as well. Also, see our antenna design guide for further in-depth details: http://www.ti.com/lit/pdf/sloa241

  • 0 in reply to Ralph Jacobi
    Prodigy 110 points

    Hello Ralph,

    Thanks for reply , yes  i tried with Q= 8 , Fc=14.5Mhz BW=1.9Mhz but unable detect VISA Platinum cards and MASTER cards  in that range also . 

    so kindly suggest best way to solve this . 

    With regards,

    Shivu 

  • 0 in reply to shivu ns1
    TI__Guru*** 135355 points

    Hello Shivu,

    When you say unable to detect, do you mean you cannot get a response to the polling command?

    What software are you using?

    Also, are you planning to EMVco certify your design?

  • 0 in reply to Ralph Jacobi
    Prodigy 110 points

    Hello Ralph,

     we are getting response from polling command but some Wavecards its in long loop its not exit from loop , once we take out of cards from antenna then only it will exit from polling loop . we faced this issue only one wave card but we have tested more than 10 to 15 different wave cards those are working fine . but only one card we facing that lissue . 

    yes we are planning to EMVco certify for our design. 

    With regards,

    shivu 

  • 0 in reply to shivu ns1
    TI__Guru*** 135355 points

    Hello Shivu,

    shivu ns1 said:
     we are getting response from polling command but some Wavecards its in long loop its not exit from loop

    Could be a protocol issue with reader software. If using TI software we do not support payment cards with it. That would need to be added.

    shivu ns1 said:
    yes we are planning to EMVco certify for our design. 

    Unfortunately due to Errata item Device#B01, the TRF7970A cannot pass EMVco certification: https://www.ti.com/lit/pdf/sloz011

    We do not have an NFC reader device that can pass EMVco, so if that is your requirement, you will need to use devices from other vendors.

  • 0 in reply to Ralph Jacobi
    Prodigy 110 points

    Hello Ralph,

    Please suggest  us how to solve this protocol issue in software if  any reference please share  (Links),  I tried all possibilities from HW side but we are facing some issues for  payment cards .

    suggest us what are various steps to test the signals for verification at the time of detection .

    With regards,

    Shivu 

  • 0 in reply to shivu ns1
    TI__Guru*** 135355 points

    Hello Shivu,

    shivu ns1 said:
    Please suggest  us how to solve this protocol issue in software if  any reference please share  (Links),  I tried all possibilities from HW side but we are facing some issues for  payment cards .

    Payment cards have a specific APDU exchange protocol that is not covered in any of our software offerings. My recollection (last I looked was 4+ years ago) both MasterCard and VISA have their own unique APDU exchanges to get data from the cards. I don't recall where the documentation for that would be, but I would strongly suspect that it is provided by each company for developers, so I would start along that path.

    We don't have any references and do not support those payment applications at all.

    What you would use API wise are the following:

    ISO_7816_4_sendAPDU
ISO_7816_4_getWriteAPDUStatus

    With those API's, you can create a custom APDU handling state machine with a structure like what you see for T4T_stateMachine in t4t_app.c.

    shivu ns1 said:
    suggest us what are various steps to test the signals for verification at the time of detection .

    You can debug with breakpoints exclusively, but I also recommend getting a logic state analyzer like Saleae's which will let you quickly get a capture that you can then scan through to see where the communication is breaking.

  • 0 in reply to Ralph Jacobi
    Prodigy 110 points

    Expected Behavior The bit duration (1 etu) as defined by ISO14443A/NFC-A air interface is supposed to be 9.44 µs (±0.5%). Issue The device fails this criterion. Measuring this value (for example, for EMVCO compliance testing), the 1 etu is approximately ≥9.587 µs and, hence, outside the given specification limits. Condition The device operates as ISO14443A/NFC-A reader/writer and as NFC-A Peer to Peer (P2P) Initiator. Implications The device fully supports ISO14443A communication. The device fail the EMVCO compliance testing as the 1-etu value is outside given range. Workaround There is no workaround identified

    Please elaborate . let me know how to test these etu.  

  • 0 in reply to shivu ns1
    TI__Guru*** 135355 points

    Hello Shivu,

    Measurements like that are done on official NFC or EMVCo test suites such as those offered by COMPRION, Keolabs, and National Instruments (who acquired Micropross). TI has run the device through multiple such suites and that is how the errata was characterized and also how our NFC stack was architected and tested.